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Inherent brittleness and low mechanical reliability usually inhibit the application of ceramic materials in many structural applications. In this work, we demonstrate that integrating crystallographic texture and second-phase toughening strategies can effectively improve fracture resistance and mechanical reliability in alumina multilayer composites. Composites consisted of equiaxed (1-x)Al2O3-xZrO2 and highly [0001]-textured Al2O3 layers were fabricated, and effects of ZrO2 amount on fracture behavior and mechanical properties of the composites were studied. Increasing ZrO2 amount x results in larger thermal expansion difference between equiaxed and textured layers. The composites with equiaxed layers containing 30 vol% ZrO2 exhibit high apparent fracture toughness Kapt, c ~11.7 MPa·m1/2 and work of fracture γWOF ~1540 J/m2, which correspond respectively to about 260% and 410% enhancements relative to those without ZrO2 addition. Moreover, adding ZrO2 remarkably reduces sensitivity of failure stress to flaw size in the multilayer composites, and the failure stress substantially increases with increasing ZrO2 content. The greatly enhanced mechanical performance achieved here can be mainly attributed to higher magnitude of compressive stresses, more crack bifurcations and longer crack deflection paths within the textured layers. This work can provide important guidelines for developing novel “bio-inspired” materials with improved fracture resistance and flaw tolerance behavior.

Aluminum foil undergoes severe plastic deformation and multiple heat treatments during processing, and the texture characteristics become very identifiable. In this research, textured AA8021 aluminum foil was obtained by adjusting the fabrication process. The anisotropic behavior of aluminum foil was studied by tensile testing. The surface morphology and texture evolution of the aluminum foil were studied before and after tensile testing by means of digital microscopy, optical profilometry and electron backscattered diffraction. The experimental results showed that compared with the samples tested at 0° and 90° to the rolling direction, the samples tested at 45° to the rolling direction exhibited lower yield strengths and flow stresses due to the “soft orientation” of most grains. Additionally, when the aluminum foil was tensile tested at 45° to the rolling direction, the shear bands on the surface of the aluminum foil were long, dense, bent and crossed. The rotation of cube grains caused the aluminum foil matrix to undergo significant geometric hardening, increasing the strain hardening index n. Additionally, the rolling texture improved the anti-thinning ability of the aluminum foil at 45° to the rolling direction, significantly increasing the ultimate strain reached in the 45° direction. These research results provide important theoretical guidance for improving the drawability of aluminum foil box-shaped parts by adjusting the microtexture under industrial conditions.

Zirconium remains the main structural material for thermal reactors due to the small capture cross section of thermal neutrons. In the period of stricter safety requirements for reactors with a simultaneous increase in operating parameters, predicting the behavior of the material in emergency situations has gained greater urgency. In this work, we measured the temperature dependence of the thermal expansion of samples cut from thick-walled tubes made of Zr-2.5% Nb alloy that were deformed and annealed in different modes. The analysis of the physical processes responsible for the shaping of the material is carried out. It was found that the anisotropic change in the linear dimensions of cubic samples both during heating and cooling is due to a change in the zirconium content in the β-phase, phase transformations α + β-Zr → α + β-Nb → β → α + β-Zr, as well as the preferred orientation of the grains of the α-phase, characterized by high anisotropy of linear expansion. It is shown that the expansion of the investigated samples upon heating in the α -phase is determined exclusively by the integral texture parameters of Kearns, and the coefficients of thermal linear expansion (TLEC) in different directions vary over a wide range from 3⋅10-6 to 12⋅10-6 K−1. During cooling at the stage of the reverse phase transformation of the β-phase into α, an increase in the size of the cubic samples in the tangential direction up to 2.3 % and a decrease in the radial direction to 1.3 % are noted, which is associated with the orientation of the α-phase grains formed during cooling in the β -matrix and anisotropy of the TLEC of the α -grains. It is shown that the orientation of the α-phase grains in the reverse β → α transformation is determined not only by the orientation of the basal axes in the initial material, but also by the spatial distribution of the prismatic axes relative to the external directions in the tube. Significant size fluctuations in different directions of the samples obtained using the technology of manufacturing channel tubes for CANDU reactors should lead to the development of significant macrostresses both during heating and cooling of the tube. The structural state of the samples deformed or annealed at 400–530 °C does not significantly affect the temperature dependence of the TLEC, but is manifested only in some of its features. In this case, completely recrystallized samples, i.e., with a recrystallization texture, in which the 2 - 0 > directions are oriented along the tube axis, are characterized by a significantly lower variation in dimensions in different directions in the temperature range 20–1200 °C.

The strain-induced martensite transformation is of great importance in the strain hardening process of ferrite based low-density steel. Based on the microstructure analysis, the texture evolution and martensite transformation behavior in the strain hardening process were studied. The results show that martensite transformation accompanied by TWIP effect and high density dislocations maintains the continuous hardening stage. As the strain increases, the texture of retained austenite evolves towards the F orientation {111} , which is not conducive to martensite transformation. After the strain of 5%, the number of austenite grains with high Schmid factor orientations is gradually increased, and then significantly reduced when the strain is over 10 % due to the occurrence of martensitic transformation, which results in a high martensitic transformation rate. However, the unfavorable orientation and the reduced grain size of austenite slow down the martensite transformation at the final hardening stage. Moreover, because of the coordination deformation of austenite grains, strain preferentially spreads between adjacent austenite grains. Consequently, the martensite transformation rate in strain hardening process is dependent on the orientation and grain size evolution of austenite, leading to a differential contribution to each strain hardening stage.

Texture formation processes at all technological stages of tube manufacture were considered. It has been established that at the stage of hot deformation and manufacture of TREX tubes, tangential and radial textures are formed, a large share of tangential component of the texture. Influence of main factors of the technological process on formation of texture and properties was established. Conditions for formation of a maximum amount of radial texture in tubes which ensure improvement of service properties of tubes were determined. To create maximum amount of radial texture in tubes, total reduction rate in passes and the wall to diameter reduction ratio (factor Q) are important. The reduction rate should be increased, especially in the last passes, to 75…85%. Heat treatment (stress relief annealing) practically does not change the tube texture.

In the present work, the tribological performance of solution treated Ti–27.96Nb–11.97Ta–5.02Zr (wt%) alloy has been assessed after 1000 m sliding at the applied load of 2N, 5N, 20N and 50N and sliding speed of 300 mm/s against Ti–6Al–4V ELI. The near-surface micro-texture evolution induced by frictional force has been investigated in detail using SEM-EBSD. According to the results, TNTZ alloy shows better tribological performance compared to Ti–6Al–4V ELI in all the applied loads. The signs of oxidation and adhesion wear were clearly observed on all the worn surfaces of the worn alloys. Low wear weight loss of TNTZ alloy at lower applied loads is due to the continuous substructure development as well as the formation of γ-fiber alignment texture along the sliding direction in absence of texture in the highly refined β grains. The results showed that the transition from γ-fiber texture to cube texture takes place with the increase of applied load to 50N and networked leading to brittle fracture and third body abrasive wear particle generation. These phenomena have a high influence on the wear rate of TNTZ alloy when the applied load increases. Neither the grain elongation nor the shear bands were formed in the subsurface of worn deformed specimens.

The influences of Sr on the microstructure, texture and mechanical properties including flow and anisotropy behavior of AZ31 alloys are investigated. Slabs containing no, 0.4 and 0.8 wt% of strontium were cast and subjected to hot rolling. Results indicate that Sr reduces the basal texture intensity (23% in the AZ31+0.8Sr alloy) and homogenizes the distribution of strain in uniaxial tension. Furthermore, Sr increases both the strength coefficient and the strain hardening exponent in all directions. In the transverse direction, enhancements are more significant. Moreover, Sr enhances the combination of tensile strength and total elongation; i.e., toughness, whether tests are performed parallel to the rolling, diagonal or transverse directions, to significant extents. Keywords: AZ31, Hot rolling, Mechanical properties, Microstructure, Strontium, Texture

This paper aims at understanding the texture evolution in extruded oxide dispersion strengthened 18Cr ferritic steel during high-temperature uniaxial compression testing at 1,423 K at a strain rate of 0.01/s based on extensive electron back scatter diffraction characterization. The α-fiber texture is observed along the extrusion direction (ED) in the initial microstructure. The flow curves generated during uniaxial compression test are used to determine the associated hardening parameters. In addition, the degree of texture evolution after deformation along the ED and the transverse direction (TD) with respect to the initial condition has been predicted using VPSC-5 constitutive model. The prediction shows that the deformation along the ED produces a dominant γ-fiber texture in contrast to the TD. This is in agreement with the experimental results where γ-fiber texture is observed, due to enhanced dynamic recrystallization at high-temperature deformation.

Variation of the texture and grain state of refractory nickel alloy ZhS6K-VI synthesized by the method of selective laser melting is studied as a function of the sintering mode, the type of hatching and heat treatment. Two types of hatching are employed, i.e., diagonal-island and checkerboard ones. The texture is studied. Orientation maps of fragments are plotted with the help of the EBSD method. Regular features of structure formation depending on the synthesis mode are determined.

In the present work, a FEI Sirion FEG-SEM equipped with a Nordlys CCD camera controlled by HKL Channel 5 software has been used to characterize the crystallographic texture of 20mm thick friction stir welded AA6082-T651 and AA5083-O. The crystallogaphic texture has been nvestigated near the top surface of the weld nugget at the shoulder affected region and near the base of the nugget in the probe affected region. The crystallographic texture in the shoulder affected region is complex in terms of determing the local reference frame of deformation and it requires complicated rotations to resemble the ideal simple shear texture. This implies the complex deformation histroy experinced in this region. However, the crystallographic texture in the probe-dominated region is simple shear texture. This implies that the deformation conditions across the whole weld nugget in this region are mianly dominated by the shear deformation generated by the probe rotation with the forward motion of the tool only playing a minor role in determining the local deformation gradient. Alternating bands between (+)and (C) was observed in the NG region of FSWed AA6082. The existence of A component is observed with an existence of strong C texture component which implies that when the C component is strong it can be associated with the A texture components.The crystallographic texture of AA5083 at both the shoulder and the probe dominated region is weak relative to that of the AA6082 .

Ag–Cu alloys of two different initial microstructures—a cast eutectic alloy (AgCu-E) and an equivolume Ag–Cu powder mixture (AgCu-P)—were deformed by high-pressure torsion. The codeformation of Ag and Cu grains led to uniform refinement and a nanolamellar microstructure for both alloys. However, the lamellar structure in AgCu-P alloys was broken at intermediate shear strains (γ > 150) by extensive shear banding. On the other hand, no shear banding was observed for AgCu-E alloy at similar microstructural refinement. At higher strains deformation induced intermixing of Ag and Cu atoms was observed. Further, three-dimensional diffraction analysis of AgCu-E alloy showed that in contrast to conventional single phase alloys, the Ag and Cu phases develop similar crystallographic texture.

We studied texture change of low-carbon steel during high-cycle fatigue by ultrasonic echo-pulse method. We received the orientation distribution function coefficients using precise ultrasonic measurements of the elastic wave propagation times. Then pole figures were constructed. It is found that the texture sharpness nonmonotonic depends on the number of loading cycles. It is shown that the texture sharpness can be used as an indicator of the structural state of the alloy.

In the present research work, constrained groove pressing as one of the sheet's severe plastic deformation is employed at elevated temperature to investigate the influence of this technique on the microstructural evolutions and mechanical properties of 2024 aluminum and AZ91D magnesium alloy sheets. With this regard, three cycles of constrained groove pressing have been conducted on these alloys' annealed sheets. Optical microscopy and X-ray diffraction were used to discuss the microstructure and crystallographic texture evolution. Results demonstrated that the average grain size of the annealed specimens was decreased to 11 µm and 14 µm after one pass at 300°C for 2024 Al and AZ91D Mg alloys, respectively. By measuring the microhardness, it was found that the annealed sample has the highest homogeneity with the minimum inhomogeneity factor 5.80 and 1.86 for the 2024 Al and AZ91D Mg alloys, respectively. The ultimate tensile strength of the annealed sheet was respectively increased up to 21% and 7% for these alloys by performing the first constrained groove pressing pass. Also, all of the mechanical properties variations are changed based on crystallographic texture evolutions.

Automated electron backscatter diffraction (EBSD) technique in a dual-beam field emission gun scanning electron microscope has been successfully used to obtain three-dimensional (3D) orientation mapping of grains in modified 9Cr–1Mo after severe plastic deformation and recrystallization. In this technique, the microstructure and micro-texture across several sections of the material were studied by means of the state-of-the-art “slice and view” methodology using grazing incidence high-energy Ga+ focused ion beam for slicing and electron beam for viewing and EBSD analysis. By combining the data from each slice, a 3D texture map could be generated by means of image reconstruction technique. The orientation map thus generated provided volumetric microstructural and micro-textural information. The 3D EBSD studies on the heavily deformed mod-9Cr–1Mo steel (cold-rolled 88%) revealed that rolled grains were elongated like plates with thickness ≤ 200 nm. Analysis of the fiber texture components in rolled specimen across the sections showed near equal preference for all fiber texture components with some enhancement of the α-fiber texture. However, by recrystallizing at 1023 K for 1 h, elongated grains along rolling direction with large diameters (~ 40 to 100 µm) were observed together with finer (size ~ 0.5 to 2 µm) polygonal grains and γ-fiber texture component dominated over other texture components.

Recently, several severe plastic deformation (SPD) techniques have been developed with the aim of incorporating grain refinement and strengthening metal forming technology into the industry without dimensional changes. Multi-channel spiral twist extrusion (MCSTE) was innovated and patented in an attempt to provide an effective, cost-saving SPD process that would attract the industrial uptake of the renowned twist extrusion (TE) method. The MCSTE process is based on the use of customized stacked disks that host non-circular cross-sectioned billets extruded through a die with a twist angle (β). Hence, an empirical study was conducted on AA1100 to investigate the influence of 4 successive MCSTE passes on the mechanical behavior and microstructural evolution of the extrudates compared to the as-received (AR) condition. Electron backscatter diffraction (EBSD) was employed for mapping the structural evolution, misorientation angles and the texture developed as a function of the processing passes. Additionally, hardness and tensile properties were evaluated and correlated with the EBSD findings. EBSD analysis revealed the formation of almost equiaxed grains after 1 pass, which were evolved into elongated grains aligned at approximately 45° relative to the extrusion direction after 2-passes. Moreover, MCSTE processing 1-pass produced a structure with 64% and 36% HAGB and LAGB, respectively, while 2-passes via MCSTE increased HAGBs to 80%. Processing 4-passes increased the amount of recovery depicted by the percentage of LABs within the grains, which was associated with a noticeable increase in the fraction of fine grains

In this study, SiC nanoparticles (∼50 nm, 3 vol%) are homogenously incorporated within an Al–Mg alloy metal matrix during multi-step friction-stir processing (FSP) to fabricate an Al-matrix surface...

Friction cladding as one of the simplest methods of surface modification with simultaneous coating application was used for surface nanostructuring. Intensive plastic deformation using a rotating wire brush (RWB) was performed during friction cladding. Brush fibers had an impulse-friction effect on the work surface with simultaneous coating application. Normalized steel samples (diameter 45 mm, width 10 mm) made of Grade 45 steel were tested for wear resistance. A copper-containing coating was applied at a circular grinder. Samples treated by various operating modes were tested at the SMC-2 friction machine using a disk-to-disk friction drive scheme. The tests showed that samples with a copper coating (C1) and a brass coating (B63) feature 2–10 times higher wear resistance in comparison than reference ones depending on the treatment mode. Samples with a brass coating (coating thickness 10–15 μm) applied in 6 passes with 2 mm interference (RWB feed on the work piece) at a sliding speed of 25 m/s demonstrated the highest strength. Smooth specimens (four series, a total of 60 pieces) made of 20CN steel were tested according to GOST 25502-82 «Fatigue Test Methods» to study the effect of friction cladding modes on endurance. Test results showed that the most effective way is surface plastic deformation with brass coating application. The endurance limit increase factor was Kυ = 1,41. It was found that steel mechanical properties (σв, σт, δ10) are not affected by coating application using friction cladding. Copper coating applied on coupling rods and plungers in hydraulic systems ensured 1,4–3,0 times longer service life, and up to 6 times longer life when applied on wave gear teeth in edge version.

The paper focuses on metal surface nanostructuring and functional coating application using a flexible tool – rotating wire brushes (RWB). This process called friction cladding implemented on lathes, grinders and other machine tools using ordinary tooling or manual angle grinders. Metallographic investigation of surface layers used 3×20×100 mm plates made of Steel 08 as study samples. Coatings were applied using the surface grinder where RWB was installed instead of an abrasive disk together with a coating material feeding device. Cylindrical samples (Steel 50) 20 mm in diameter were machined by angle grinders installed on the sliding carriage of the lathe. Optical microscopes and the JSM-6490 LV electron-scan microscope (ESM) were used for metallographic research. Electron microscopic studies were performed by replica technique using the Tesla BC-613 electron microscope. X-ray diffraction analysis was performed on the Dron-3 diffractometer. Measurements and surface roughness analysis were performed according to the GOST R ISO 25178 method on the Bruker Contour GT K1 unit. The surface structure, texture and microtopography of copper and brass coatings deposited using a flexible tool on a steel base were investigated. The average coating thickness was 20–25 μm, microhardness was about 6800 MPa for the copper coating and 9000 MPa for the brass coating with particle sizes ranging from 0,3 to 0,6 μm. The crystallographic texture of the coating reproduces the texture of the steel base material. Investigation of sample surface microtopography before and after coating showed that the brass coating substantially smoothes out the surface, but the initial microtopography is changed insignificantly. Copper coating microtopography differs substantially from the initial one.

Fracture toughness studies of line-pipe steels are extremely crucial as line-pipes are exposed to extreme conditions in application. The effects of crystallographic texture and constraint on fracture toughness of API X70 line pipe steel were investigated in this study. The J-integral method was considered to quantify the fracture toughness across orientations and thicknesses of the investigated steel. The difference in the crack initiation toughness clearly demonstrated the presence of strong anisotropy. Further the counteracting effects of thickness and delamination on constraint were found to govern fracture mechanism as well as the fracture toughness of the specimens. The anisotropy in toughness was investigated with macro-texture measurements of the specimens. The major crystallographic textures and their influences on fracture toughness were analyzed. Amongst the observed texture components, strong intensities of {113} component of α-fiber was identified as the major reason for anisotropy in fracture toughness. The distribution of volume fractions of {112} component also showed a strong correlation with the fracture toughness across orientations.

The accident at Fukushima Daiichi in 2011 highlighted the increased interest in predicting the materials properties under extreme conditions. In this work, it is considered the behaviour of cubic samples cut from the wall of channel tubes made of Zr-2.5% Nb alloy during heating and cooling in the temperature range of 20-1200 °C. The anisotropy of changes in the dimensions of cubic samples in different structural states has been studied. Thermal tests were carried out in three mutually perpendicular directions: radial, tangential and axial. The structural state of tubes was estimated from the features of their crystallographic texture. The significant anisotropy of the size change is observed in the Zr-2.5%Nb alloy product with an unstable crystallographic texture of deformation due to the α↔β-phase transformation inhomogeneity. In the case of complete recrystallization and orientation of the axes along the tube axis, the anisotropy of the dimensions change is minimal, due to uniform nuclei formation of new phases in different orientations.

The impact toughness of a Ti+Nb HSLA steel plate, conventionally hot rolled in the austenitic region, were measured at four different directions at 0 °C, −20 °C and −40 °C respectively. The microstructure was characterised using light optical microscope, scanning electron microscope (SEM) followed by evaluation of hot rolled texture using X-ray diffraction (XRD) and orientation distribution function (ODF) obtained from electron back-scattered diffraction (EBSD). The anisotropy in the yield strength (YS) and Charpy impact toughness (CVN) were examined in the light of orientation distribution function (ODF) obtained from EBSD. The skeleton lines, showing intensity distribution, f(g), of the fcc-to-bcc transformation texture, namely the α-fiber (⟨110⟩∥ RD), the γ-fiber (⟨111⟩∥ ND) and e-fiber (⟨110⟩∥ TD) are considered to explain the observed anisotropy along with microstructural features. The major components like, {112}⟨110⟩, {113}⟨110⟩, {332}⟨113⟩, {111}⟨112⟩ and {111}⟨110⟩, their relative intensity distribution, are found to cause the observed anisotropy in yield strength and impact toughness. A stronger presence of {113}⟨110⟩ component of the α-fiber over relatively weaker {332}⟨113⟩ component of the e-fiber further augments the observed toughness anisotropy. In absence of any microstructural banding, strong the presence of {113}⟨110⟩ and {112}⟨110⟩ can also cause delamination in ductile fracture mode.

In this work, the microstructure and corrosion resistance of phosphate conversion coatings on the cross-sectional surface (CS), the rolled surface (RS) and the slanted surface (SS) of rolled AZ31 magnesium alloy were compared. Results demonstrate that most grains on the rolled surface (RS) conform (0001) orientation, which renders a lowest electrochemical reactivity; while the cross-sectional surface (CS) and the slanted surface (SS) exhibited a preferential orientation of ( 01 1 ‾ 0 ) and ( 1 ‾ 2 1 ‾ 0 ) , which renders a higher electrochemical reactivity. The variation of electrochemical reactivity affects the nucleation rate of crystals, thus altering the compactness and corrosion resistance of phosphate conversion coating on different surfaces. The conversion coating on the RS exhibits the worst corrosion resistance.

In this study, relationships between microstructure, texture, and hardness of hot-rolled AZ31 alloy were investigated. It was found that the grain size decreased into the ultra-fine domain after 60% hot deformation, reaching a grain size of 1 μm. Several dynamic recrystallization (DRX) mechanisms activated after 40% and 60% deformations including discontinuous dynamic recrystallization (DDRX), twin dynamic recrystallization (TDRX), continuous dynamic recrystallization (CDRX), and particle stimulated nucleation (PSN). With increasing the thickness reduction, the intensity of basal texture first increased, then slightly decreased, and finally significantly increased to 15.7 multiple of random density. The average misorientation angle decreased when the thickness reduction increased owing to the formation of a very strong {0001} basal texture. With increasing the strains, the average microhardness increased because of decreasing grain size and increasing twin fraction and shear band density. There were no differences between the hardness values of RD–TD and RD–ND planes for AZ31 samples after 10% and 40% hot rolling and these samples were isotropic. After 60% deformation, the hardness of the RD–TD plane (73.5 HB) was higher than that of the RD–ND one (68.4 HB) that resulted in hardness anisotropy due to the generation of very strong basal texture.

In the present work, for the first time, the effect of asymmetric rolling at room temperature on the microstructural evolution, texture, hardness, tensile properties, and fracture surface of AA7075 alloy was investigated. It was found that the width of grains significantly decreased to 2.6 μm by 60 % asymmetric rolling. Also, shear bands in the RD-ND (rolling direction – normal direction) plane of AA7075 after 40 % and 60 % asymmetric rolling were evident. In addition, the size of iron-rich intermetallic particles was reduced with increasing thickness reduction. Microstructure and texture revealed that new grains through continuous dynamic recrystallization (CDRX) are created after 40 % and 60 % strain. On the one hand, after applying only 10 % thickness reduction, average hardness demonstrated 75 % enhancement. On the other hand, maximum yield (611 MPa) and ultimate tensile (644 MPa) strengths achieved in the 60 % deformed sample, demonstrating 287 % and 73 % improvement compared to the initial sample. These results were due to strain hardening, dynamic/static precipitation, and Fe-rich particle fragmentation. The Portevin-Le Chatelier (PLC) effect is reduced with increasing the strain. Interestingly, the 40 % deformed sample revealed the serrated flow. For this reason, the 40 % rolled sample has a lower total elongation (4.4 %) than the 60 % deformed sample (11.1 %). The tensile strength of the 40 % deformed sample (575 MPa) was lower than the 10 % and 20 % rolled samples (581 and 594 MPa, respectively). This result was owing to the occurrence of softening mechanisms, strengthening the Goss {110}⟨001⟩ component, and weakening the Copper {112}⟨111⟩ orientation after 40 % asymmetric rolling. By increasing the thickness reduction up to 40 %, the number of dimples decreased. However, the fracture surface of the 60 % deformed sample showed a noticeable amount of small dimples.

In the present study, commercially pure micrometer-sized magnesium powder was reinforced with different volume percentages of TiO2 nanoparticles using powder metallurgy process followed by hot extrusion. The powder metallurgy processing of the materials includes blending the powders together followed by compaction and high temperature sintering in inert atmospheric condition. Microstructural analysis of the extruded reinforced magnesium has revealed that the TiO2 nanoparticles enhanced the recrystallization process in the magnesium matrix and also significantly refined the grain morphology. Analysis of X-ray diffraction spectrum of the extruded powder processed magnesium has revealed significant pyramidal plane texturing parallel to the extrusion direction due to the incorporation of TiO2 nanoparticles. Texture coefficient calculated from the X-ray diffraction spectrum using Harris texture index formula revealed that the presence of increasing volume percentage of TiO2 nanoparticles reinforcement gradually relaxed the strong alignment of basal plane and enhanced the pyramidal plane texturing parallel to the extrusion direction.

This paper reports the evolution of microstructure and texture in Nickel-Cobalt electrodeposits fabricated by pulse electrodeposition (PED) technique and the correlation of these attributes with the magnetic properties. The structural and microstructural investigation using X-ray diffraction and transmission electron microscopic studies indicate the presence of nanocrystalline grains and nano-twins in the electrodeposits. Convoluted Multiple Whole profile fitting reveals an increase in dislocation density and twin density with increasing cobalt content in the as-deposited samples. Strengthening of fibre texture and weakening of fibre texture with increasing cobalt concentration has been observed with X-ray texture analysis. A corresponding significant increase in the saturation magnetization and coercivity observed with increasing cobalt content. A significant improvement in the soft magnetic character in the electrodeposits in terms of increase in saturation magnetization and decrease in coercivity has been observed with thermal annealing. (C) 2017 Elsevier B.V. All rights reserved.

Aluminum (Al)-based metal matrix composites reinforced with multiwalled carbon nanotubes were developed by powder metallurgy route. The Al and multiwalled carbon nanotubes powder mixtures were consolidated under a load of 565 MPa followed by sintering at 550℃ for 2 h in inert atmosphere. Al–1, 2, and 3 wt.% multiwalled carbon nanotube composites were developed. In the present study, the microstructure, mechanical properties, sliding wear behavior, and crystallographic texture of various Al–multiwalled carbon nanotube composites were investigated. The multiwalled carbon nanotubes produced by low-pressure chemical vapor deposition technique and the various sintered composites were characterized using scanning electron microscope, high-resolution transmission electron microscope, X-ray diffraction, differential scanning calorimetry and thermogravimetric analysis, Raman spectroscopy, and Fourier transform infrared spectroscopy. A significant improvement in relative density, Vickers microhardness, and wear resistance of the composites up to addition of 2 wt.% of multiwalled carbon nanotubes was observed. The deterioration in these properties beyond 2 wt.% of multiwalled carbon nanotubes was possibly due to the agglomeration of multiwalled carbon nanotubes in the Al matrix. The tensile strength of Al–multiwalled carbon nanotube composites continuously decreases with the addition of multiwalled carbon nanotubes. The decrease in tensile strength can be attributed to the detrimental effect of Al4C3 formed at the interface of the Al matrix and the multiwalled carbon nanotubes which will cause premature failure of the composite. The addition of multiwalled carbon nanotubes altered the crystallographic texture of the composites. The residual stresses in the various composites were found to be compressive in nature and also show improvement up to addition of 2 wt.% multiwalled carbon nanotubes in the Al matrix.

This study presents the numerical homogenization of spherical and cubical statistical volume element (SVE). Numerical homogenization with periodic boundary conditions for spherical and cubical SVEs has been employed. The lamellar structure of eutectic Copper (Cu)-Silver (Ag) has been focused for the investigation of deformation behaviour and texture evolution. The initial texture for cold-drawn eutectic Cu-Ag composite has been approximated by a set of 200 discrete orientations. The comparison of deformation behaviour and the crystallographic texture has been investigated for two different SVEs. It is demonstrated that the SVEs with cubical shape induce an anisotropy when compared with the spherical SVEs. The numerical results for cubical and spherical SVEs in terms of deformation behaviour and crystallographic texture are in good agreement with the experimental observations.

The regularities of texture formation in FeGa-based alloys during deformation at medium degrees (about 60 %) and primary recrystallization were studied. Deformation was realized by two methods: rolling and hydrostatic extrusion to study the deformation behavior and the texture formation processes. After deformation, the samples were subjected to annealing to initiate primary recrystallization. The structure and texture after deformation and recrystallization were studied using EBSD technique. It was shown that FeGa-based alloys have a greater tendency to form {hkl} texture during primary recrystallization, compared to other wide-used soft magnetic materials with body-centered cubic (bcc) lattice. Alloying by boron enhances this tendency and results in a uniform texture after recrystallization. As a result, a high level of functional properties was achieved through the implementation of cost-effective deformation and annealing operations.

High strength and high toughness steels can be developed by warm caliber rolling in ferrite region. However, high deformation resistance limits its application. In the present study, warm rolling was applied to plate rolling which is more suitable for industrial production to develop high strength and high toughness steels. To reduce deformation resistance, warm rolling was carried out in dual phase region. We elucidate here the evolution of microstructure and crystallographic texture and their influence on mechanical properties of microalloyed steel subjected to warm rolling. The study suggests that high strength and high toughness can also be obtained by warm rolling in the dual phase region. Elongated ultrafine microstructure and intense α-fiber texture component and γ-fiber texture component can be obtained through warm rolling. The main mechanism of microstructure evolution during warm rolling was dynamic recovery. Reducing warm rolling temperature can refine grain size, enhance α-fiber texture component and weaken γ-fiber texture component. Warm rolling can greatly enhance strength by ~64–158 MPa compared to the conventional controlled rolling (CR) process, and the warm-rolled plates had high elongation in spite of high strength. The toughness was improved because of grain refinement and delamination. Delamination can induce ductile fracture at low temperature, and delay the occurrence of brittle fracture such that high toughness is obtained in steel plates. The effect of warm rolling temperature and impact test temperature on delamination and impact property was elucidated.

Additive manufacturing offers a unique way of anisotropic microstructure control with a high degree of design freedom. This study demonstrates that application of suitable process parameters and laser sources in selective laser melting may favour either one sharp single component texture, more uniformly distributed crystal orientation, or a combination of the above in a preferred gradient, which influence the mechanical properties. It is shown that transitions in microstructure, texture, and properties in fabricated Inconel 718 functionally graded components can be obtained at relatively small or large length scales, depending upon the functional gradient desired in a particular application. Results obtained by electron backscatter diffraction showed distinct regions of coarse elongated grains with a strong (001) orientation uniformly embedded in randomly distributed fine grained matrix. Mechanical tests in the form of hardness, tensile and in-situ digital image correlation tests showed steep transitions in the developed Inconel gradients. The observed mechanical properties were found to be primarily dependent on the grain size and texture and are superior to the cast samples for both laser sources. The developed process strategy can be further applied to design functional gradients with selected tailored properties and to account for directional anisotropy of solidified components. Keywords: Additive manufacturing, Ni-base alloys, Crystallographic texture, Functional grading

The combined effect of microstructure and crystallographic texture on the anisotropy in Charpy impact toughness has been studied in two hot-rolled low-carbon steel plates having different sulphur contents: 0.03 wt% S in high-sulphur, HS, steel and 0.01 wt% S in low-sulphur, LS, steel. Sub-size Charpy impact specimens were prepared from the rolled plates along 0°, 30°, 60° and 90° to the rolling direction and tested over the temperature range of +40 °C to −196 °C. Microstructure, inclusions and crystallographic texture have been characterized on the plane parallel to the fracture plane of each sample. The variation in upper shelf energy (USE) was more severe (∼69%) in HS steel due to the presence of coarse and elongated MnS inclusions. Crystallographic texture, especially, higher fraction of alpha- to gamma-fibre texture and stronger cube texture resulted in stronger variation in ductile to brittle transition temperature (DBTT) in LS steel (by ∼26 °C). Increase in the fraction of {001} planes of the crystals on the fracture plane of the sample increased the DBTT by helping the cleavage crack propagation. On the other hand, increase in the fraction of {110} planes of the crystals on the shear planes (inclined at 45° to fracture plane) increased the USE by promoting the plastic deformation.

The method of orientation microscopy (EBSD) is used to study the texture of low-carbon, low-alloy pipe steel sheets with a bainitic structure made by controlled thermomechanical processing. The specimens analyzed are inclined or not inclined towards forming separations (secondary cracks) in a fracture during mechanical testing. Formation of separations during failure of steel with a bainitic structure is connected with the presence in the material of regions with uniform orientation (001) extended in the cold rolling direction. Formation of the regions is a consequence of features of γ→α shear transformation that commences at special boundaries between deformed austenite grains.

Low-carbon bainitic steel with effective grain size of ~2.0 µm and strong //RD (rolling direction) transformation texture was obtained by adopting ultra fast cooling following non-recrystallization rolling. The steel exhibited higher tensile strength of ~840 MPa and lower ductile-to-brittle transition temperature of ~−106 °C in comparison with the steel that had no distinct texture with effective grain size of ~4.5 µm. High intensity of {110} planes normal to the rolling direction were formed as a result of the strong {114}~{223} transformation texture and effectively inhibited the main crack propagation by ductile fracture mechanism. The existing {100} planes parallel to the rolling plane led to the impact fracture delamination at −20~−100 °C, which improved the low temperature toughness.

In this study, different textures of Ti6Al4V alloy at the same microstructure have been developed through heat treatment in the α + β phase region. Scanning electron microscopy and macrotexture analysis were performed on three orthogonal surfaces. The corrosion performance of different surfaces was assessed by open circuit potential, electrochemical impedance spectroscopy, and potentiodynamic polarization in PBS solution. The obtained results showed that the basal texture corrosion rate (3.6 × 10−5 mm/year) was 6 times lower than those of near prismatic texture. SEM investigation of the corroded surfaces showed the formation of a thick crack-free passive layer on the surface having basal texture.

The proposed linearized yield function considers the crystal lattice constants and the parameters of crystallographic orientation of material and has simplified form, which makes it suitable for technological calculations of sheet metal forming processes. It is shown that the Lode coefficient is determined not only by the stress state, as in the case of an isotropic material, but also depends on anisotropy parameters, which reflects the elastic constants of the crystal lattice and the crystallographic orientation of the structure.

International audience; This study investigated the mechanisms of formation of the microstructure and texture of an Inconel 625 manufactured by additive manufacturing, using laser-based powder bed fusion. The resulting texture has a quadratic symmetry and a composite organization of grains. Some elongated grains have their 〈100〉 aligned along the build-up direction and grow from the middle of the melt pool, whereas the others are inclined with a lower texture. This is explained on the basis of usual solidification mechanisms. The overall texture is not very pronounced (texture index of 1.24) but sufficient to influence ultrasound wave propagation in a measurable manner. The difference is the most pronounced between the slow and fast quasi transverse waves. The contribution of two main factors influencing the anisotropy, namely the anisotropy of the single crystal and the shape of the grains, are discussed in the paper.