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Severe plastic deformation (SPD) with strong shear component is required to promote both grain refinement and texture randomization. When Asymmetric rolling (AR) is applied as asymmetric accumulative roll bonding (AARB), it enables the production of architectured microstructures and metallic composites. Finite element (FE) simulations of AR and AARB were employed to understand the influence of pass thickness reduction (PTR) on the through thickness variation of the velocity gradient. The influence of the PTR up to a total thickness reduction of 50% and the effect of a single 50% reduction step in a bi-layer bonding condition was analyzed. The influence of these process parameters on the strain and rigid body rotation components was compared with the experimental data obtained on an AA1050 aluminum. A better shear to compression ratio across the sheet thickness is achieved by PTRs lower than 30%; at a PTR of 50% the texture is dominated by the frictional shear generated at the roll-sheet interface and the process has a stronger compressive character. This indicates that simple ARB followed by AR with smaller PTRs should generate a better shear distribution than AARB alone.

Evolved eggshell strength is greater in several lineages of obligate avian brood parasites (birds that lay their eggs in other species' nests) than in their hosts. Greater strength is typically indirectly implied by eggshell thickness comparisons between parasites and hosts. Nevertheless, there is strong evidence that the eggshell structural organization differentially influences its mechanical properties. Using instrumental puncture tests and SEM/EBSD and XRD techniques, we studied the most relevant eggshell mechanical, textural, ultrastructural and microstructural features between several host species and their parasitic cowbirds (Molothrus spp.). These parasitic species display different egg-destructive behaviors, reducing host reproductive fitness, including the more frequently host-egg puncturing M. rufoaxillaris and M. bonariensis, and the host egg-removing M. ater. The results, analyzed using a phylogenetic comparative approach, showed interspecific patterns in the mechanical and structural features. Overall, the eggshells of the two egg-puncturing parasites (but not of M. ater) were stronger, stiffer and required greater stress to produce a fracture than the respective hosts' eggs. These features were affected by eggshell microstructure and ultrastructure, related to the increase in the intercrystalline boundary network acting in cooperation with the increase in palisade layer thickness. Both structural features generate more options and greater lengths of intercrystalline paths, increasing the energy consumed in crack or fissure propagation. The reported patterns of all these diverse eggshell features support a new set of interpretations, confirming several hypotheses regarding the impact of the two reproductive strategies (parasitic versus parental) and parasitic egg destruction behaviors (more versus less frequently puncturing).

Many metallurgical processes produce characteristic dislocation accumulation, with heterogeneous spatial and orientation distributions and further development of microstructures after heat treatment. Recovery and recrystallisation behaviours are direct consequences of those uneven dislocation distributions. The Electron BackScatter Diffraction (EBSD) technique can be used for the characterisation of such microstructural features, including: Density of Geometrically Necessary Dislocations (GND), Kernel Average Misorientations (KAM), Grain Orientation Spread (GOS), Grain Average Misorientation (GAM), Grain Reference Orientation Deviation (GROD - Angle) and GOS/D, where D is an assumed characteristic grain length. Production of Fe3%Si alloys with a Goss texture, essential step in the manufacture of electrical transformers, requires several different processing stages, including the one called primary recrystallisation, a key process preceding abnormal grain growth. The structure of grains and different microstructural aspects of the recrystallisation stage will provide the conditions for development of the Goss orientation during abnormal grain growth. In the present work we use GOS, GAM, GROD, GOS/D, GND and KAM, calculated from EBSD scans performed on cold rolled Fe3%Si alloys subject to increasing heat treatment times, to characterise the kinetics of recovery and primary recrystallisation in an Fe3%Si alloy. Difficulties in the interpretation of these results may arise from the interactive competition between various microstructural features. Hardness measurements were also performed in order to validate recovery and recrystallisation evolution by classical methods. It was found that the global GOS (i.e. including grains of all orientations) shows changes which can be related to those observed in the hardness for high annealing temperatures but it is not sensitive to microstructure evolution occurring at low temperatures. Meanwhile, GND undergoes changes at all annealing temperatures and, remarkably, it responds to the recovery that GOS cannot detect at low temperatures. The GAM parameter seems to follow better the microhardness results. When grains belonging to different texture components are analysed, gamma fibre grains are the first to recrystallise and alpha fibre grains the last. LAY DESCRIPTION: Many metallurgical processes produce characteristic dislocation accumulation, with heterogeneous spatial and orientation distributions. Further development of such microstructures occurs with subsequent heat treatments. Recovery and recrystallisation behaviours are directly affected by consequences of those uneven dislocation distributions. The Electron Back Scatter Diffraction (EBSD) technique can be used for the characterisation of such microstructural features using different magnitudes that describe locally or globally misorientations between various locations in the material. In search of the best parameters [among them: Density of Geometrically Necessary Dislocations (GND), Kernel Average Misorientations (KAM), Grain Orientation Spread (GOS), Grain Average Misorientation (GAM), Grain Reference Orientation Deviation (GROD - Angle) and GOS/D, where D is an assumed characteristic grain length], we characterised the kinetics of the recovery during the 1st recrystallisation in an Fe3%Si alloy. It was found that the global GOS (i.e. including grains of all orientations) shows changes that can be related to the advance of recrystallisation on the other hand, the GND (KAM, GAM etc.) parameter seems to better follow the progress of recovery phenomenon. When grains belonging to different texture components are analysed, gamma fibre grains are the first to recrystallise and alpha fibre grains the last.

In the present work, we report the preparation of a novel titanium-based alloy, namely Ti25Nb10Zr, by cold crucible levitation melting technique. The cast alloy consists of a complex microstructure with large Beta phase grains (54%, 50-150 μm) with a regularly connected net of Alpha′ (orthorhombic, 46%) phase running along boundaries and across the grains and keeping a regular misorientation with respect to the Beta phase. An intermeshed 51% Alpha and 49% Beta phases with lamellar microstructure were found by annealing. The electrochemical tests showed that both alloys were affected by the corrosion process. A good corrosion resistance in SBF at 37 °C was found for the cast form. The cast alloy is more resistant when immersed into solutions with pH2 and pH7, while the annealed one is resistant in pH5 solution. Surface potential of both alloys is negative, with the annealing process leading to a slight decrease of that property. Collectively, the biological results indicate a more favorable viability on cast form as compared to annealed one, suggesting that the cast alloy is promising for biomedical applications. Fil: Bolmaro, Raul Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Parau, Anca C.. National Institute of Research and Development for Optoelectronics; Rumania Fil: Pruna, Vasile. Romanian Academy. Institute of Cellular Biology and Pathology Nicolae Simionescu; Rumania Fil: Surmeneva, Maria A.. National Research Tomsk Polytechnic University; Rusia Fil: Constantin, Lidia R.. National Institute of Research and Development for Optoelectronics; Rumania Fil: Avalos, Martina Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Cotrut, Cosmin M.. National Research Tomsk Polytechnic University; Rusia. University Politehnica of Bucharest; Rumania Fil: Tutuianu, Raluca. Romanian Academy. Institute of Cellular Biology and Pathology Nicolae Simionescu; Rumania Fil: Braic, Mariana. National Institute of Research and Development for Optoelectronics; Rumania Fil: Cojocaru, Danut V.. National Research Tomsk Polytechnic University; Rusia Fil: Dan, Ioan. SC R&D Consulting and Services; Rumania Fil: Croitoru, Sorin. Tehnomed Impex Co; Rumania Fil: Surmenev, Roman A.. Romanian Academy. Institute of Cellular Biology and Pathology Nicolae Simionescu; Rumania Fil: Vladescu, Alina. National Institute of Research and Development for Optoelectronics; Rumania. Romanian Academy. Institute of Cellular Biology and Pathology Nicolae Simionescu; Rumania

A low carbon steel was processed by Cold Rolling (CR) and Asymmetrical Rolling (ASR) at room temperature until 200 µm thickness reduction using multiple rolling passes of 25 µm. ASR process induced a soft curvature with a 45.7 mm length and 128.8 mm radius, while the CR process did not show any curvature. Materials showed differences in the strain path as well as in the texture and microstructure evolution, not only concerning the mode of deformation but also across the sheet thickness. The hardness and tensile tests indicated a higher strength after processing by ASR than CR for the same thickness reduction. Changes in dislocation densities and grain size were more pronounced in the surface neighborhoods of the material processed by ASR than the as-received (AR) and CR conditions, while the grain size and the dislocation densities of the CR material were more homogeneous across the sheet thickness. Synchrotron measurements allowed to build dislocations and crystal size distribution functions. These functions demonstrated that for the surface zones for ASR condition, high dislocation densities correspond to the grains developing rolling texture components. In contrast, the highest dislocations densities for the center zone formed inside the smallest crystals with shear texture orientations. By ASR, a heterogeneous material with hard surfaces was generated using multiple small thickness reductions in a narrow and thick sheet. In contrast, with CR, a homogeneous hardness increase was obtained throughout the sheet's thickness, avoiding curvature in the material. It was found that high and heterogeneous distributions of geometrically necessary dislocations (GNDs) across the sheet thickness were responsible for the ASR material additional hardening.

It is well known that a balance between the generation of low-angle and high-angle grain boundaries (LABG and HAGB) is achieved in materials undergoing a severe plastic deformation (SPD) process. It is also observed that most annealed materials evolve from a substantial fraction of LAGB at the early deformation steps towards a steady state in which an equilibrium between LAGB and HAGB fractions is attained. In the present work, such a balance is analyzed for different alloys, i.e., Cu, Al, and Fe based. A mathematical expression is proposed for the amount of LAGB and HAGB as a function of the strain impaired which in turn can be used to predict the number of passes (especially for ECAP) or the amount of total deformation for any SPD process necessary to attain a steady microstructure. The model seeks to serve as a first approximation of the mechanical and microstructural properties of ultrafine grain metal materials.

In this work asymmetric accumulative roll bonding (AARB) was applied to a AA1050 aluminum up to ten cycles at 350 and 400°C. The texture was measured by x ray diffraction and EBSD. Hardness and tensile tests characterized the strain distribution and bonding efficiency. At 350 °C the microstructural refinement was stabilized after four cycles and mean grain sizes of one micron and a saturation yield strength of 160 MPa was achieved. At 400°C grain growth took place yielding a bimodal microstructure with mean grain size of 9 microns. During repeated bonding cycles recovery and dynamic recrystallization were observed and extra shear in the interfacial region yielded a fairly well homogeneous strain distribution and weak shear texture across the sheet for both temperatures. The strongest component in both cases was the rotated cube orientation. The last bonding surface was the weakest bond but adding an extra 50% reduction step to the process increased the interfacial strength considerably.

Commercially pure grade 2 titanium in sheet form was processed by equal channel angular sheet extrusion (ECASE) up to two passes at room temperature. The ECASE process generated a heterogeneous state of deformation, mainly affecting the sheet metal edges´ vicinity. The deformation heterogeneity gave rise to notable microstructural changes throughout the sheet thickness with high densities of twins located around 600 μm from the sheet edges. At the same time, the middle zone was kept free of twins. The highest twin density generated with the ECASE process corresponds mostly to tension twins of type 10 1 ¯ 2 10 1 ¯ 1 oriented towards the extrusion direction. The heterogeneous structure produced a material strength increase of 200 MPa, maintaining a uniform deformation zone of 10%. The good strength-ductility combination was related to a heterogeneous distribution of geometrically necessary dislocations (GNDs) between the hardest and softest areas. The edge areas presented greater GNDs of type ⟨a⟩ on the twins' exterior than in their interior while in the middle zone, the highest GND densities grouped around triple points and grain boundaries. It was found that the grains with the most significant capacity to nucleate twins and store GNDs were those with the c-axis of the crystals parallel to the normal direction (ND). According to the Hall-Petch relationship, the strength improvement of the heterogeneous material comes from the grain size reduction mainly due to twins induced by deformation around the edge areas.

Strain partitioning and texture evolution of AISI 201 austenitic stainless steel were investigated upon cold rolling up to a true strain of e = 0.92. e-martensite formation is the main work hardening mechanism at low strains ( e = 0.11). With increasing strain, the volume fraction of α’-martensite increases with a sigmoidal-like behavior. Remaining untransformed austenite is intensely fragmented by mechanical microtwins. The in-grain misorientation increases for all phases up e = 0.51 and then levels off for further strain. Strain partitions evenly between austenite and α’-martensite during cold rolling. X-ray texture measurements revealed that austenite develops Goss, Brass and S texture components up to the largest investigated strain. The presence of Brass component at the highest deformation seems to be assisted by mechanical twinning. The texture components of α’-martensite belong to the α - and γ - fibers. Texture evolution of e-martensite was followed by electron backscatter diffraction data and results show that texture evolves up to e = 0.51 and remains nearly unchanged at larger strains, similarly as observed for austenite and α’-martensite.

In a polycrystal, the heterogeneity of plastic deformation in a particular grain is greatly enhanced by adjacent grains that constrain the grain's local behavior, often imposing orientation gradients. This work aims to characterize and quantify the local orientation gradients near grain boundaries (GBs). Electron backscatter diffraction (EBSD) measurements were made on a 0.67 mm thick aluminium-killed drawing quality (AKDQ) steel sheet subjected to different loading paths that are typical of forming operations. A statistical analysis shows that a considerable fraction of the analyzed GB profiles can be described by an orientation profile with a constant slope near the GB. In order to quantify this behavior, as well as the degree of localization, two new parameters, based on the local orientation gradient assessed by EBSD, are proposed: BET (boundary effective thickness) and GAS (gradient average severity). These parameters should be considered together, the BET as an effective thickness of the GB zone where the orientation gradient takes place and the GAS as a measure of the magnitude or severity of the orientation gradient. Additionally, the GAS parameter shows a strong correlation with the accumulated macroscopic strain for the investigated deformation levels and loading paths, while the BET profile clearly reveals the influence of the GB on the misorientation profiles. Tension and biaxial stretching results lead to a BET value between 1.5 and 2 μm. Finally, it is shown that the local misorientation in the GB zone, on both sides of the GB line, is disperse and it does not correlate simply with misorientation or even the slip-transfer geometry across the GB. Moreover, the observed average local misorientation dispersions in GB zones are different for each loading condition. Fil: Signorelli, Javier Walter. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Roatta, Analía. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: de Vincentis, Natalia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Schwindt, Claudio Daniel. Universidad Nacional del Sur. Departamento de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Avalos, Martina Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Bolmaro, Raul Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Bozzolo, N.. Ecole Des Mines de Paris; Francia

The microstructural characteristics of deformation-processed materials highly influence their mechanical properties. For a complete characterization of a microstructure both local and global information must be gathered, which requires the combination of different analysis techniques. X-ray and Electron Backscatter Diffraction were used in the present paper to characterize the deformation induced in a cold rolled F138 austenitic stainless steel sample. The results obtained using laboratory and synchrotron X-ray sources were compared and combined with EBSD quantitative results, allowing the global and local characterization and orientation dependence of the deformation microstructure. A particular behavior was observed in the XRD data corresponding to the planes with < 220 >∥ ND, likely due to a smaller amount of defects accumulated in the crystals with that particular orientation. EBSD was used to separate the scans data into partitions and to calculate misorientation variables and parameters, showing that this behavior can be attributed to a combination of larger grain sizes, lower local boundary misorientations and dislocation densities for crystals having < 220 >∥ ND. Several conclusions, of general validity for the evaluation of microstructure anisotropy, can be extracted from the results. Fil: de Vincentis, Natalia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Avalos, Martina Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Benatti, Emanuel Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Kliauga, A.. Universidade Federal do São Carlos; Brasil Fil: Brokmeier, H. G.. Institut für Werkstoffkunde und Werkstofftechnik; Alemania Fil: Bolmaro, Raul Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina

We study the deformation inducing heterogeneity in an aluminum alloy 6063-T6 in the form of a sheet processed at room temperature by equal channel angular sheet extrusion (ECASE) up to a maximum equivalent strain of 1.86 following route C. The through thickness strain distribution showed higher strains in the edge vicinities than in the sheet core. The texture was heterogeneous between the edges and the sheet core with a strong cube component in the initial deformation stages, and a rolling texture with the S component in the sheet edges. Different microstructural characteristics, like grain size, average misorientation, and fraction of high angle grain boundaries (HAGB), decreased by increasing the deformation. The geometrically necessary dislocation (GND) calculations corroborated the existence of a heterogeneous microstructure along the sheet thickness, giving rise to gradients of plastic deformation which allowed to obtain a good strength-ductility relationship. It was demonstrated that ECASE process was a good alternative to produce heterogeneous microstructures. The material heterogeneity was found not to be randomly distributed across the sheet thickness but rather showing higher dislocation concentration and bigger grain size reductions in the edge’s vicinities than in its middle zone.

An austenitic stainless steel was processed at room temperature by equal channel angular sheet extrusion (ECASE). The microstructure evolution was heterogeneous across the sheet thickness with a higher martensitic transformation in the zones closer to the edges than in the sheet core due to the deformation-induced martensite (DIM) phenomena. The material heterogeneity induced by one ECASE pass gave a good strength-ductility relationship. Fil: Muñoz Bolaños, Jairo Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Higuera Cobos, Oscar Fabián. Universidad del Atlántico; Colombia Fil: M'Doihoma, Rose. Clermont Auvergne University School of Engineering; Francia Fil: Avalos, Martina Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Bolmaro, Raul Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina

The influence of electropulses in situ on the drawing process of copper wires was investigated, with the aim of avoiding time consuming annealing thermal treatments. It was found that with the application of electropulses, tensile and drawing forces were reduced and the plasticity of the wire was improved. Meanwhile, compared with conventional drawing, hardness decreased. With the electropulsing treatment, no differences were found in the material&rsquo, s resistivity. The microstructure exhibited similar grain size despite the joule effect, although some changes were found in the low and high angle grain boundaries. Compressive residual stresses were found on the surface during the assisted process, consequently, these specimens were expected to have a better performance under fatigue fracture. Therefore, we have found the first evidence of the advantages of this hybrid technique for pure copper wire drawing and, ultimately, to replace the conventional drawing annealing process with a more time effective electropulse-assisted drawing process.

The local misorientation and orientation gradient development near grain boundaries (GBs) are analyzed in a deep drawing quality steel sheet (AKDQ) subjected to interrupted tensile tests in a notched sample. The microstructure is studied using electron backscatter diffraction (EBSD) with subgrain-level spatial resolution. The evolution of misorientation accumulation for particular GBs was traced in grains located in different zones inside the notch, identifying the effective area of influence of GBs inside the neighboring grains. A local study was performed, and the evolution in misorientation development near GB was investigated. The results show a low correlation between GB width and sharpness of the orientation gradient with the mesoscopic strain, but instead orientation gradients between GB zones and the interior of the grains were observed with increasing strain. The increase in severity observed in some GBs can be related to dislocation pile up development, which reduces the permeability of a boundary to dislocation transmission. Fil: de Vincentis, Natalia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Roatta, Analía. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Bolmaro, Raul Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Signorelli, Javier Walter. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina

The effect of ECAE on the properties of an Fe-15Mn-5Si-9Cr-5Ni shape memory alloy (SMA) was investigated. Phases, texture, microstructure, critical temperatures, mechanical and SM properties after severe deformation, and the effect of annealingwere analysed. One ECAE pass develops a shear texture. There is a large 〈101〉 component in the extrusion direction,which is near the ideal 〈414〉 for martensitic transformation activation. The pressing did not refine the previous as cast structure but introduced dislocations and ε-martensite. Thus, the stress to induce the Γ → ε martensitic transformation, σΓ → ε, reached 620 MPa, and the quantity of ε-martensite formed after compression was limited. The degree of shape recoverywas reduced,while the reverse transformation temperatures increased. Heat treatments above 800 ° C activated recrystallization. As annealing temperature increased, new grains nucleated and grew, reaching a size of 53 μm after heating to 1000 ° C. For this condition,σΓ → ε was 430 MPa, and the best shape recovery was achieved, 64%. Fil: Druker, Ana Velia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; Argentina Fil: Baruj, Alberto Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina. Universidad Nacional de Cuyo; Argentina Fil: Isola, Lucio Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; Argentina Fil: Fuster, Valeria de Los Angeles. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; Argentina Fil: Malarria, Jorge Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; Argentina Fil: Bolmaro, Raul Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; Argentina

Accumulative Roll Bonding (ARB) is one of the so-called severe plastic deformation (SPD) processes, allowing the production of metals and alloys with ultrafine (micro-nano) structures. Materials with ultrafine grains present attractive properties like the simultaneous increase in strength and ductility. Our interest in these materials is focused on their microstructural evolution during ARB processing, eventually responsible for the enhancement of those mechanical properties. In the current work we follow the evolution of the microstructure in an interstitial-free (IF) steel deformed by ARB after consecutive processing cycles, by means of Electron BackScatter Diffraction (EBSD) and X-ray diffraction (XRD). Particularly, we present results related to texture, grain (GS) and domain sizes, grain boundary character, density of Geometrically Necessary Dislocations (GND), Grain Orientation Spread (GOS), lattice parameters, microstrain, dislocation density and their spatial arrangement. After 5 ARB cycles the system shows a microstructure constituted mainly by submicrometric grains with high angle boundaries and low presence of dislocations inside the grains. Fil: Cruz Gandarilla, Francisco. Instituto Politécnico Nacional; México Fil: Salcedo Garrido, Ana María. Instituto Politécnico Nacional; México Fil: Bolmaro, Raul Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Baudin, Thierry. Centre National de la Recherche Scientifique; Francia. Université Paris Sud; Francia Fil: de Vincentis, Natalia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Avalos, Martina Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Cabañas Moreno, José G.. Instituto Politécnico Nacional; México Fil: Mendoza León, Héctor. Instituto Politécnico Nacional; México

This study evaluates the influence of the structural changes promoted by a solution heat treatment (ST) on recrystallization and grain growth during annealing of the 3105 Al alloy subject to asymmetric rolling. Optical Microscopy, Scanning Electron Microscopy (SEM)/X-Ray Energy Dispersive Spectroscopy (EDS), X-Ray Diffraction (XRD), dilatometric analysis and Vickers hardness tests were used to evaluate the microstructural and mechanical properties. The influence of solution heat treatment on grain growth kinetics could not be evaluated because of incomplete recrystallization due to the chosen annealing parameters. Fil: Diniz, Saulo Brinco. Instituto Militar de Engenharia; Brasil Fil: Benatti, Emanuel Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; Argentina Fil: Andersan Dos Santos, Paula. Instituto Militar de Engenharia; Brasil. Universidade Federal Fluminense; Brasil Fil: Bolmaro, Raul Eduardo. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; Argentina Fil: Da Silva, Luis Celso. Universidade Federal Fluminense; Brasil Fil: Meirelles, Bruna Godoi. Votorantim Metai; Brasil

The aging treatment effect on an AA6063 aluminum alloy was studied by characterizing the microstructure and mechanical properties. The aging impact increased the alloy strength from 100 MPa in the solubilization state to 200 MPa in the aged state. The aging treatment effect, in addition to the formation of precipitates, gave rise to a high number of geometrically necessary dislocations at (GND), and different concentrations of Si and Mg inside some grains. The early fracture of the aged material concerning the solubilization condition was demonstrated by the multiple formations of strain peaks and a high dislocation annihilation rate. The most significant strength contributions to the aged alloy came from precipitates, followed by the solid solution, dislocations, and grain size.

A sheet-shaped austenitic stainless steel (ASS) was processed by one ECASE pass. In this way, larger deformations were introduced close to the sheet edge vicinities, while the middle zone remained less affected by the deformation. The heterogeneous deformation produced larger amounts of deformation induced martensite (DIM) at the sheet edges, resulting in a heterogeneous structure along the sheet thickness. Tensile tests revealed that after the deformation process the material increased its yield strength more than 3 times from 200 MPa in its initial state to ~690 MPa after one ECASE pass. Tensile tests for the processed material in different zones of sheet thickness revealed the existence of two types of materials, one more resistant and less ductile (near the edges) and other more ductile, but less resistant (in the middle zone). Because of the heterogeneity, higher dislocation densities were found in the edges than in the middle of the sheet, giving rise to a plastic deformation gradient in which the region near the edge is capable of withstanding greater plastic deformations by generating a plastic instability as soon as the deformation starts. Through a rule of mixtures, it was found that the greatest strength contribution of the heterogeneous material came from the dislocations on the bcc martensite developed near the sheet edges.

Accumulative Roll-Bonding (ARB) and Asymmetric Rolling (AR) techniques were combined to produce ultrafine-grained aluminum sheets with the mechanical characteristics of a Severe Plastic Deformation (SPD) process. Temperature and number of bonding cycles were varied to promote grain refinement, texture randomization and high-quality sheet bonding. Finite element simulation for a single pass was performed to clarify the strain distribution differences between symmetric and asymmetric roll -bonding. The microstructure and crystallographic texture were measured by Electron Backscatter Diffraction (EBSD) and X-ray diffraction. Hardness and tensile tests characterized strain distribution and bonding efficiency. A fine grain structure with a mean grain size of 1.0 μm was achieved at 350 °C, whereas a coarser grain structure was obtained at 400 °C. The grain size and shape distribution were linked to enhancing the mechanical strength in a transversal direction. During repeated bonding cycles at both temperatures, extra shear in the interfacial region yielded favorable homogeneous strain distribution and a weak shear texture across the sheet. Rotated-cube orientation was the strongest component in both processing temperatures. To increase the interfacial strength, mainly on the last bond interface, an extra 50% reduction step was added. This improved the adhesion in the last bonding interface, and thus enhanced the ductility. These findings helped to provide a basis for determining the processing conditions for aluminum alloys.

An Aluminum alloy 6063T6 was processed at room temperature by Equal Channel Angular Sheet Extrusion (ECASE). Microstructure evolution was investigated by Electron Back Scattering Diffraction (EBSD), and X-ray diffraction analysis. The texture evolution was heterogeneous and represented by a mix of rolling and shearing components through the sheet thickness. Ncorr™ calculations showed higher shear strains close to the edges than in the sheet core, in agreement with the through thickness expected variation. The Geometrically Necessary Dislocation (GND) calculations corroborated the existence of a heterogeneous microstructure through the sheet thickness. Fil: Mendez Muñoz, Jose Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Avalos, Martina Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Bolmaro, Raul Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina

The thermal stability of ARMCO iron processed by equal-channel angular pressing (ECAP) up to a true strain of 16 was investigated by differential scanning calorimetry (DSC). Particularly, the analysis was focused on deriving the recrystallization behavior (onset, peak, and offset temperatures) at three different heating rates (10, 20, and 40 °C/min). Additionally, the stored and activation energies were calculated. As well, the microstructure and the tensile response were evaluated at different numbers of passes before and after annealing heat treatment to assess any significant grain growth and its influence on the material ductility. The different energy contributions (dislocations, grain boundaries, and vacancies) were calculated, being verified that the main contribution came from vacancies. Fil: Muñoz Bolaños, Jairo Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina. Universidad Politécnica de Catalunya; España Fil: Higuera Cobos, Oscar Fabián. Universidad Politécnica de Catalunya; España. Universidad del Atlántico; Colombia Fil: Hernández Expósito, Ana. Universidad Politécnica de Catalunya; España Fil: Boulaajaj, Ahmed. Fundació CTM Centre Tecnologic; España Fil: Bolmaro, Raul Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Dumitru, Florina D.. National Institute for Research and Development in Environmental Protection; Rumania Fil: Rodriguez Calvillo, Pablo. Arcelor Mittal Global R&D Gent; Bélgica Fil: Jorge, Alberto Moreira. Universidade Federal do São Carlos; Brasil. University of Grenoble Alpes; Francia Fil: Cabrera, José María. Universidad Politécnica de Catalunya; España

ARMCO iron processed by ECAP up to a maximum equivalent strain of sixteen ECAP passes following route Bc was investigated by Electron Back Scattering Diffraction (EBSD), Transmission Electron Microscopy (TEM), TEM-EBSD and X-ray Diffraction Line Profile Analysis (XRDLPA). Different values of grain size were obtained with each technique. The lower values were obtained by XRDLPA whereas, the higher values were achieved by TEM-EBSD. Dislocation densities were also calculated by different techniques obtaining values of statistically stored and geometrically necessary dislocations as a function of the deformation. All differences in values allowed a better understanding of the nature of microstructures of the materials processed by severe plastic deformation (SPD). Mechanical properties showed a considerable increment in the material strength due to the progressive reduction of the grain size because of the Continuous Dynamic Recrystallization (CDRX) mechanism and the increment in the dislocation density.

The presence of second phases in FeMnSi-based systems has been widely discussed in the literature, and also in our previous works. In this manuscript, various specimens of an Fe-15Mn-5Si-9Cr-5Ni wt.% (nominal composition) shape memory alloy were processed by different thermomechanical treatments in order to identify the phases present in each condition. TEM-EDS results indicate that the chemical composition of the second phase we found in all cases is close to 19Mn-xSi-12Cr-5Ni at. %, with x varying between 5 and 11, and Fe balance. This is compatible with a Fe5Ni3Si2 type intermetallic phase. It forms in a temperature range between 600 and 900 °C, independently of the thermomechanical processing and the coexisting phases. Rietveld refinement of X-ray patterns was done using Maud software, and the phase was found to be isostructural to the pi-phase Cr3Ni5Si2 with space group P213 and lattice parameter equal to 0.6227(7) nm. Phase quantification, crystallite size and accumulated microstrain were also computed as a convenient set of variables, necessary for improving refinement quality. Relevant microstructural information, i.e. stacking fault and twinning probabilities, along with dislocation density, were calculated for austenite, the matrix phase, contributing to the reliability of the determination of the crystallographic characteristics of the second phase. Fil: Fuster, Valeria de Los Angeles. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; Argentina Fil: Druker, Ana Velia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; Argentina Fil: Baruj, Alberto Leonardo. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Área de Energía Nuclear. Instituto Balseiro; Argentina Fil: Malarria, Jorge Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; Argentina Fil: Bolmaro, Raul Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina. Universidad Nacional de Rosario. Facultad de Ciencias Exactas, Ingeniería y Agrimensura; Argentina

The present investigation reports on the microstructure evolution, texture development, the nature of the grain boundaries and the tensile and deep drawing behaviour of commercial AA1050 Al processed by Equal Channel Angular Pressing (ECAP) plus rolling. Although in terms of final mechanical strength ECAP and rolling are indistinguishable, the deformation path is substantially different, and this has important consequences on both microstructure and texture. From the spatial distribution of high angle grain boundaries (HAGB) and low angle grain boundaries (LAGB), the fine microstructure and the crystallographic texture, it was concluded that the microstructure is oriented according to the external imposed flow: a spin movement in the ECAP process, which promotes the rotation of the cells inside the original grain, followed by a sliding movement caused by the rolling, leading to grain elongation. The ECAP process is more suitable to promote a higher fraction of HAGBs, and the same time as it reduces the intensity of the bulk crystallographic texture. As a consequence an increase of the penetration depth and deformation strain, as measured by the Erichsen test, was observed in samples processed by 8 ECAP passes, characterized by low texture intensity and a high degree of dynamic recrystallization. Fil: Vega, M. C. V.. Universidade Federal do São Carlos; Brasil Fil: Bolmaro, Raul Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Ferrante, M.. Universidade Federal do São Carlos; Brasil Fil: Sordi, V. L.. Universidade Federal do São Carlos; Brasil Fil: Kliauga, A. M.. Universidade Federal do São Carlos; Brasil

The microstructure developed during severe plastic deformation results in improved mechanical properties because of the decrease in domain sizes and accumulation of defects, mainly dislocation arrays. The characteristic deformation stages observed in low stacking fault energy (SFE) face centered cubic (FCC) materials are highly influenced by the development of the primary and secondary twinning that compete with dislocation glide. In this paper, a low SFE F138 stainless steel is deformed by equal channel angular pressing (ECAP) up to 4 passes at room temperature (RT) and at 300°C to compare the grain refinement and twin boundary development with increasing deformation. Tensile tests were performed to determine the deformation stages reached by the material before and after ECAP deformation, and the resulting microstructure was observed by TEM. X-ray diffraction and EBSD, average technique the first and local the second one, were used to quantify the microstructural changes, allowing the determination of diffraction domain sizes, dislocation and stacking fault densities and misorientation indices, which lead to a complete analysis of the deformation introduced in the material, with comparative correlations between various microstructural parameters. Fil: de Vincentis, Natalia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Kliauga, A.. Universidade Federal do São Carlos; Brasil Fil: Ferrante, M.. Universidade Federal do São Carlos; Brasil Fil: Avalos, Martina Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Brokmeier, H. G.. Institut für Werkstoffkunde und Werkstofftechnik; Alemania Fil: Bolmaro, Raul Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina

Dislocation densities have been determined and hydrogen traps have been characterized in an API 5LX60 steel. The steel has been subjected to different degrees of plastic strain ( ɛ P ) by cold rolling. The dislocation densities has been determined by the analysis of the peak broadening on X-Ray diffractograms. The traps have been characterized through the measurement of hydrogen permeation transients and fitting of a trapping model to the experimental data. The relationship between hydrogen traps and dislocation density is discussed.

Fe-Mn-Si based alloys exhibit the shape memory effect (SME) through a γ(FCC) ↔ ɛ(HCP) stress-induced martensitic transformation. Studies carried out with single crystals have shown that the extent of shape recovery depends on the crystal orientation: it is nearly absent if the stress acts along the [001] direction and almost perfect when applied in the [414] direction. Therefore, certain crystallographic textures in polycrystals may contribute to better shape recovery with less applied stress. On the other hand, the texture is a consequence of the thermal and mechanical material processing history. This study analyzes how the particular forming process and the consequent texture development affects the amount of stress-induced ɛ martensite in an Fe-15Mn-5Si-9Cr-5Ni shape memory alloy. Besides determining the quantity of martensite produced, we measured the critical transformation temperatures and analyzed the effect of the manufacturing procedures on the SME properties.

The aim of this work was to analyze the evolution of texture of an aluminium AA1050 processed by ECAP and further recrystallization in search of optimum processing conditions to improve formability. The initial material was processed by two different routes: the first set of samples came from a hot rolled coil with a mixture of cube, copper and brass textures and the second from roll casting, exhibiting a strong brass texture. The ECAP deformation followed routes A (no sample rotation between passes), Ay (no sample rotation between passes but keeping the normal to rolling direction parallel to the transverse extrusion axis) and Bc (with a 90o sample rotation around the extrusion axis between passes). Texture evaluation was performed by x-ray analysis and results were analyzed by regular texture and orientation distribution function calculations. The normal and planar anisotropy were measured for the deformed and annealed samples. ECAP orientations were generated mostly by rotation around the transverse axis. 〈111〉//ND; orientations can be generated from S, Goss or copper textures but not from brass or cube textures. Therefore route A and starting with the hot rolled or rolled textures should be considered if 〈111〉//ND orientations are desired. Using route Bc, rotating the existing orientations into a favorable position can generate the desired fiber. The strength of a texture after ECAP depends on the orientations of the initial texture, however the correlation starts vanishing after various ECAP steps and the texture finally smoothes out. When 〈111〉//ND was more intense there was an improvement in the planar anisotropy.

Severe Plastic Deformation (SPD) techniques are widely used nowadays because of the mechanical properties improvements caused by grain refinement and development of dislocation arrays. Diffraction techniques can be used to assess the changes registered in the microstructure through these methods. Two sets of samples of F138 austenitic stainless steel were analyzed in this paper: one set was deformed by ECAE up to two pressings at room temperature, and the other set was cold rolled to 70% reduction and annealed at 600, 700, 800 and 900 °C for 1 h. The microstructural changes were determined using X-Ray diffraction and EBSD, combining both, global and local information and characterizing domain sizes, dislocation and stacking fault densities and misorientation degree and distribution caused by the different thermomechanical processing. It was observed that, despite cold rolling and 2 ECAE passes rendered rather similar von Mises deformations, the microstructure through each deformation method was different: 2 ECAE passes seem to be more effective for grain refinement and generation of equiaxed domains than cold rolling. The more significant twin activation observed in the former sample, because of continuous strain path change, may explain the difference, although dislocation densities and mechanical properties did not differ substantially for both deformation methods. Fil: de Vincentis, Natalia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Avalos, Martina Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Kliauga, A.. Universidade Federal do São Carlos; Brasil Fil: Brokmeier, H. G.. Institut für Werkstoffkunde und Werkstofftechnik; Alemania. Helmholtz Zentrum Geesthacht; Alemania Fil: Bolmaro, Raul Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina

Fil: Barrios, Celina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Santa Fe. Instituto de Desarrollo Tecnologico para la Industria Quimica (i); Argentina

Microstructural characterization by combined EBSD and X-ray diffraction analysis is shown for an FCC material deformed by rolling and further heat treatment on air. The wide variety of x-rays sources combined with EBSD allows some correlations between microstructural parameters to be withdrawn by carefully analyzing x-ray peak broadening. The combination of both techniques provides a deeper understanding of anisotropic accumulation of dislocation arrays on a deformed F 138 stainless steel. The anisotropy results in a smaller peak breadth for crystal orientations with [110] planes contained on the rolling plane, further explained as resulting from a lower storage of dislocations. After heat treatment the effect is reverted and the formerly less misoriented orientations become more uniformly oriented revealing a faster dislocation migration and annihilation and/or trapping Behandelt wird die mikrostrukturelle Charakterisierung mittels kombinierter EBSD- und Röntgenbeugungsanalyse für einen durch Walzen und Wärmebehandlung an Luft verformten kfz-Werkstoff. Die Kombination eines breiten Spektrums an Röntgenquellen und EBSD ermöglicht auf der Grundlage einer sorgfältigen Analyse der Röntgenpeakverbreiterung die Ableitung einiger zwischen mikrostrukturellen Parametern bestehenden Korrelationen. Die Kombination beider Techniken sorgt für ein tieferes Verständnis der anisotropen Ansammlung von Versetzungsanordnungen in rostfreiem Stahl F 138. Aus der Anisotropie ergibt sich eine geringere Peakbreite für in der Walzebene enthaltene Kristallorientierungen mit [110]-Ebenen, die auch als Folge einer geringeren Einlagerung an Versetzungen erklärt werden kann. Nach der Wärmebehandlung kommt es zu einer Umkehrung des Effekts und die zuvor wenig fehlorientierten Ausrichtungen richten sich einheitlicher aus und weisen eine schnellere Versetzungswanderung und -annihilation und/oder Trapping (etwa: „Einfangen“) auf Fil: Bolmaro, Raul Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Avalos, Martina Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: de Vincentis, Natalia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Kliauga, Andrea M.. Federal University of São Carlos; Brasil Fil: Brokmeier, Heinz Günter. Institut für Werkstoffkunde und Werkstofftechnik; Alemania

In situ neutron diffraction experiments were performed to follow the annealing behavior of iron deformed by equal-channel angular pressing at room temperature using route Bc to a total von Mises strain of evM = 9.2. The temperature was varied from room temperature to 1223 K (950 °C), while neutron diffraction data for quantitative texture analysis were collected at a given temperature when holding for 5 minutes. Pole figures and orientation distribution function maps from neutron diffraction and electron backscatter diffraction measurements were used to follow the changes in crystallographic texture and grain size during annealing. In situ neutron diffraction experiments allowed understanding and identifying texture-related changes that occur during recrystallization, grain growth, and phase transformation in iron.

The aim of this work was to analyze the evolution of texture and the deformation anisotropy of a AA1050 after ECAP and further recrystallization. The initial material was processed by two different routes: the first set of samples came from a hot rolled band with a mixture of cube, copper and brass textures and the second from roll casting and presented a strong brass texture. The ECAP deformation followed routes A, Ay (no rotation between passes but keeping the normal to rolling direction parallel to the transverse extrusion axis) and Bc. Texture evaluation was performed by x-ray analysis. Results were analyzed by regular texture and orientation distribution function calculations. The deformation anisotropy was measured by tension tests with specimens oriented 0, 45 and 90o to the extrusion direction.

The growth of recrystallization nuclei towards the deformed matrix generally does not proceed isotropically. Local disturbances in the migration along grain boundaries lead to the formation of protrusions. This important aspect in recrystallization is rarely explored in the literature, especially in the sense of understanding which microstructural mechanisms explain its formation. The aim of this work is to study the formation of protrusions during the recrystallization of a niobium oligocrystal. A coarse-grained niobium plate was cut out from the longitudinal section of an electron-beam cast ingot. Five coarse grains (A, B, C, D and E) were randomly selected for this study to evaluate likely orientation effects on protrusion formation. The plate was cold rolled with several passes up to 50% thickness reduction. The sheet was then cut into two parts. The former was straight rolled until 70% thickness reduction while the latter was rotated 90° around the normal direction with respect to the initial rolling direction. Important orientation and rolling mode effects were noticed regarding their recrystallization behavior. Protrusions were more abundant in the cross-rolled specimens. It was not possible to identify and associate significant differences regarding either CSL-type special boundaries or highly-misoriented boundaries ahead of the boundaries showing protrusions.

Modern to Pleistocene Amiantis purpurata shells collected in Bahı´a San Antonio (Patagonia, Argentina) were studied by X-ray diffraction (XRD), optical and electron microscopy, electron microprobe analyses, and microindentation, in order to characterize early diagenetic changes and mechanical resistance. The sole crystalline phase is twinned aragonite showing pseudohexagonal symmetry. The regularity of the crystallographic texture decreases in older samples, but average crystallite size does not increase. The microstructure, which is dominantly crossed lamellar, is progressively replaced by a more randomly oriented grain aggregate. Compositional profiles across the shell show gradients in Sr, Na, S, and Cl, whereas Mg and P are more evenly distributed. Each shell layer has a distinct chemical signature. A marked decrease in the concentration of all of these elements, along with flattening of profiles, is evident as age increases. Vickers microhardness is lowest in modern specimens, showing at the same time the least chipped regions; older shells become harder and more fragile. All of these changes are attributed to postdepositional modifications by dissolution-recrystallization processes mediated by a thin film of water in a vadose environment. Microstructural adjustments are more sluggish than chemical modifications produced by diagenetic processes, whereas microhardness rapidly reaches high values,probably due to the early degradation of organic compounds from the shell. Our study shows that aragonitic shells that retain their primary mineralogical composition have undergone subtle chemical and microstructural changes. A very small amount of calcite was produced during grinding for XRD. Care should therefore be taken when seeking calcite as evidence of diagenetic changes. Fil: Bayer, María Sol. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones En Ciencias de la Tierra; Argentina Fil: Colombo, Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones En Ciencias de la Tierra; Argentina Fil: de Vincentis, Natalia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Física de Rosario (i); Argentina Fil: Duarte, Gonzalo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Física de Rosario (i); Argentina Fil: Bolmaro, Raul Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Rosario. Instituto de Física de Rosario (i); Argentina Fil: Gordillo, Sandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones En Ciencias de la Tierra; Argentina

Strain-induced martensite (SIM) and its reversion in a cold-rolled AISI 201 austenitic stainless steel was studied by means of magnetic properties, light optical (LOM) and scanning electron (SEM) microscopy, electron backscatter diffraction (EBSD), texture measurements, and Vickers microhardness testing. According to Thermo-calc predictions, the BCC phase (residual δ-ferrite and SIM) is expected to be stable until 600 °C. The current material was cold rolled up to 60% thickness reduction and submitted to both isothermal and stepwise annealing up to 800 °C. Magnetic measurements were taken during annealing (in situ) of the samples and also for their post mortem conditions. The Curie temperatures (Tc) of residual δ-ferrite and SIM have similar values between 550 and 600 °C. Besides Tc, the focused magnetic parameters were saturation magnetization (Ms), remanent magnetization (MR), and coercive field (Hc). SIM reversion was found to occur in the range of 600-700 °C in good agreement with Thermo-calc predictions. The microstructures of the material, annealed at 600 and 700 °C for 1 h, were investigated via EBSD. Microtexture measurements for these samples revealed that the texture components were mainly those found for the 60% cold rolled material. This is an evidence that the SIM reversion occurred by an athermal mechanism. Fil: Souza Filho, I. R.. Universidade de Sao Paulo; Brasil Fil: Sandim, M. J. R.. Universidade de Sao Paulo; Brasil Fil: Cohen, R.. Universidade de Sao Paulo; Brasil Fil: Nagamine, L. C. C. M.. Universidade de Sao Paulo; Brasil Fil: Hoffmann, J.. Karlsruher Institut für Technologie; Alemania Fil: Bolmaro, Raul Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Sandim, H. R. Z.. Universidade de Sao Paulo; Brasil

A strong α-fiber I texture with components from {0 0 1} 〈 1 1 0 〉 β 1 to {1 1 2} 〈 1 1 0 〉 β 1 was developed in a polycrystalline Cu–13Al–5.5Ni–1Ti (wt%) shape memory alloy by hot extrusion at 800 °C (followed by recrystallization). Nearly fully recoverable strains up to the order of 6%, associated with cubic to monoclinic martensitic transformation β1→ β1′, have been measured by thermal cycling under constant load experiments. Such a degree of strain recovery is typical of single crystals or polycrystalline arrays with a low degree of grain constraint, such as highly textured, “bamboo” like, extruded materials. The reversible transformation strains reached about 68% of the upper bound predicted by a Sachs-type model which averages the most favorable martensite variants in each grain, taking into account their orientation and disregarding interactions between them. Due to the strong texture introduced in the material, such high values of recoverable transformation strains are obtained even for specimens having a grain size/thickness ratio of ∼0.05, producing relatively high grain constraint.

The dislocation density of ferritic–martensitic oxide dispersion strengthened ODS-Eurofer steel was evaluated by using the modified Williamson–Hall method (peak broadening analysis). Measurements were performed in several metallurgical conditions (ferritic and martensitic structures). The monochromatic X-ray radiation was provided by a synchrotron source. The results match qualitatively with those provided by Vickers microhardness measurements and metallographic inspection using transmission electron microscopy.

The crossed lamellar microstructure of mollusk shells shows a very complex hierarchical architecture constituted of long rod-shaped aragonite crystals stacked parallel to each other inside each first order lamella, which are almost perpendicular to the ones contained in parallel neighboring lamellae. To better understand the construction and properties of the crossed lamellar microstructure we have performed a detailed study to determine the crystallographic characteristics and their evolution during shell growth using scanning electron microscopy, transmission electron microscopy and X-ray diffraction texture analysis. The arrangement of crystals is rationalized by a set of twin law relationships between aragonite crystals. Specifically, the aragonite rods, or third order lamellae within each first order lamella, internally consist of polysynthetic twins bounded by {1 1 0} mirror planes. In turn, the polysynthetically twinned aragonite crystals also show a constant crystallographic orientation with respect to aragonite crystals in adjacent first order lamellae. It can be seen as another twin law in which crystals from adjacent lamellae are bounded by (1 1 0) planes but with their c-axes rotated within this plane by 30°. Thus there are two sets of twin laws that relate crystal units at lower (third order lamellae) and higher (first order lamellae) length scales. These hierarchical relationships play a crucial role in the construction, organization and properties of this complex microstructure. The later orientational relationships have never been described in geological aragonite and are only found in biogenic materials with a crossed lamellar microstructure. Their occurrence is probably determined by the presence of shell organic components which regulate crystal growth and may favor unusual crystallographic relationships.

The aim of the present work is to analyze the evolution of texture after ECAP and post deformation heat treatment of an AA1050 alloy produced by roll casting. The initial plate exhibited a weak cube texture at the surface, decreasing in its intensity toward the sheet center, where the deformation texture consisted of Brass and Copper components. ECAP-deformation employed one to four passes at room temperature, following route A in a = 120o die. Texture evaluation was performed by x-ray analysis and by EBSD, using transverse cross section scans. Only the central part of the plate was studied. Results were analyzed by regular texture and orientation distribution function calculations. After 1, 2 and 4 passes the texture changed to a strong {111}// TD and after recrystallization at 350oC for 1 h this main orientation was maintained.

The phase transformation of low-carbon steels is evaluated by means of computer simulations performed with a viscoplastic self-consistent (VPSC) code. The simulations allow calculating micromechanical data at high-temperature deformation that are currently inaccessible through experiments. The micromechanical data are later on used in phase transformation computer codes to evaluate the pre-eminence of certain transformation variants following different criteria. The texture results are compared with experimental results available in the literature. The main fibers and components develop and behave differently depending on the selection of hardening laws, fragmentation criteria, active slip systems, etc. The results are compatible with high-temperature textures characteristic of a high stacking fault energy (HSFE)–like alloy and selection of variants based on the activity of the high-temperature slip systems.

Strips of Cu–13Al–5Ni–1Ti (wt.%) of about 400 μm thickness were obtained by twin-roll casting directly from the melt. Temperature-induced transformations under constant tensile load show a larger deformation, associated with the reversible martensitic transformation, for strips annealed at 700 °C and 900 °C than for the as-cast samples. This effect is partially ascribed to relaxation of internal stresses produced by the rapid solidification, some recovery of short-range disorder and microstructural changes related to Ti-rich X-phase precipitates. On the other hand, the strips show a columnar grain morphology and annealing leads to an increase of texture intensity related with the increase in elongation rate. Columnar grains are mostly aligned with the 〈 0 4 0 〉 R 18 / / 〈 1 0 0 〉 D O 3 directions.

The objective of this work is to study the texture and microstructure evolution of an IF steel deformed by Accumulative Roll Bonding (ARB) using Electron Backscatter Diffraction. Texture changes occur with increasing number of ARB cycles. For the early cycles, the main components are the α and γ fiber components characteristic of steels. With increasing the number of ARB cycles a tendency towards a random texture is obtained. In the initial state, the mean grain size is 30 μm and after 5 cycles it decreases to 1.2 μm. For the first ARB cycles, the fraction of high angle grain boundary is low but it increases with the number of cycles to about 80% for 5 cycles. The Kernel Average Misorientation (KAM) has no appreciable changes with the number of ARB cycles for all the texture components. Fil: Cruz Gandarilla, F.. Instituto Politécnico Nacional; México Fil: Salcedo Garrido, A. M.. Instituto Politécnico Nacional; México Fil: Avalos, Martina Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Bolmaro, Raul Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; Argentina Fil: Baudin, T.. Centre National de la Recherche Scientifique; Francia. Université Paris Sud; Francia Fil: Cabañas Moreno, J. G.. CINVESTAV; México Fil: Dorantes Rosales, H. J.. Instituto Politécnico Nacional; México