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Hagihara K., Nakano T.. Control of Anisotropic Crystallographic Texture in Powder Bed Fusion Additive Manufacturing of Metals and Ceramics—A Review. JOM, https://doi.org/10.1007/s11837-021-04966-7., Additive manufacturing (AM) enables the production of complex, net-shape geometries. Additionally, in AM of metal and ceramics, which has received less attention, the microstructure and texture of the product can be arbitrarily controlled by selecting appropriate process parameters, thereby enabling unprecedented superior properties. This paper discusses recent progress pertaining to texture evolution mechanisms and control methods, with an emphasis on selective laser melting. One of the unique characteristics of AM is that the texture can be varied as a function of position within the product by controlling the scan strategy. The transient behavior of the texture and the factor used to control it via the scan strategy are discussed. In addition, the texture evolution behavior of face- and body-centered cubic as well as noncubic materials is discussed. The importance of the crystallographic “multiplicity” of the preferential crystal growth direction is described to understand the evolution behavior of the texture in such materials.

The influence of crystallographic texture on the total amount of solute segregated at the grain boundaries (Xgb,tot) and consequently the weighted grain boundary energy (γw) of a nanocrystalline material is investigated. Toward this end, two different 3D nanostructures, one with random crystallographic texture and the other with {111} texture, were generated. The grain boundary misorientation distribution was obtained from both the 3D nanostructures and converted into an equivalent grain boundary energy distribution using the data from Olmstead et al. It was found that both Xgb,tot and γw are higher for the nanostructure bearing random texture vis-a-vis the {111} texture. This has implications in the development of thermally stable nanocrystalline materials. The effect of texture is also discussed through a case study on the Ni–W system by invoking the nanocrystalline stability criterion proposed by Kalidindi and Schuh.

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.

The effect of crystallographic texture on the corrosion performance of the Ti6Al4V alloy with a typical bimodal microstructure has been studied on three orthogonal surfaces of the rectangular sample. The optical microscopy (OM) and scanning electron microscopy (SEM) observations revealed that the same microstructure is developed on three surfaces via heat treatment. The crystallographic planes, which are located in parallel to each surface, have been evaluated through macrotexture analysis. The electrochemical measurements showed that the RD-ND surface (i.e., surface normal to transverse direction), in which $$ \left\{ { 0 0 0 2} \right\} $$ and $$ \{ 11\bar{2}0\} $$ crystallographic planes are placed in parallel to the surface, has the lowest corrosion rate equal to 2.2 × 10−5 mm/year. In contrast, the corrosion rate of the TD-ND surface, which is normal to the rolling direction, with $$ \left\{ { 1 0\bar{1} 0} \right\} $$ planes in parallel to the surface is ~ 15 times greater than that of the RD-TD surface. Electrochemical impedance spectroscopy (EIS) results showed that the greater corrosion resistance of different surfaces is mainly dependent on the passive layer properties formed on each surface.

Tension-compression fatigue tests were conducted on forged (F-950) and rolled (R-950) Ti-6Al-4V alloys. The role of basal texture, produced by forging, was compared with prismatic texture, produced by rolling, on microstructurally short fatigue crack growth initiation and growth resistance. The fatigue life of R-950 alloy proved to be higher than that of F-950 alloy. Major differences in fatigue crack growth rate were detected in the short fatigue crack region at crack lengths of below 100 µm (F-950 alloy showing low resistance). To quantify the effect of texture alone, the opening/closure behaviour of a microstructurally small crack was analysed from the data obtained by combining an automatic in situ observation system with a digital image correlation technique. This analysis showed the crack opening stress of both alloys to be close to identical in the short fatigue crack growth region, nullifying the effect of crack closure. To study the effect of texture, cross-sectional electron backscatter diffraction analysis was performed at crack initiation sites. The results revealed that in F-950 alloy, short fatigue crack growth proceeded along basal planes that had similarly-oriented grains, whereas in R-950 alloy, short fatigue crack growth did not follow prismatic planes: the orientation varied.

This paper investigates the effect of crystallographic texture on the corrosion product morphology and corrosion behavior of AZ31 magnesium alloy after immersion in simulated body fluid for 3 days. The microstructure and macrotexture analyses are performed through optical microscopy and x-ray diffraction methods, respectively. The polarization test evaluated the corrosion, and the FESEM electron microscope equipped with EDS was used to investigate the morphology of the corrosion products. According to the results, the morphology of calcium phosphate deposit as a corrosion product at the surface with basal texture was a porous cauliflower shape. In contrast, the calcium phosphate deposit at the surface of the nonbasal texture was uniform and nanoworm-like. The corrosion rate at the basal texture surface was higher than the nonbasal one, which is attributed to the difference in the morphology of calcium phosphate film.

The paper is devoted to the study of the mechanical, microstructural, and bio-corrosive behavior of low-alloyed Zn–Mg biodegradable surgical wires for bone reconstructions. Three biodegradable alloys with different magnesium content have been studied, their production technology has been developed and the product properties have been determined. The technology includes casting, extrusion, hot and cold drawing of the wire, and the product surface finishing. The paper shows the most important stages of the process (i.e., extrusion and drawing) in detail. The technological parameters have been selected based on the results of the computer modeling. The flow stress–strain curves of extruded materials have been obtained at various strain rates and temperatures. Two drawing technologies have been compared. The first one is the room temperature conventional wire drawing. In the second one, the first few passes have been made at an elevated temperature and the rest at room temperature. This allowed avoiding the breaking of the wire during the first passes (a typical issue of the conventional technology for these alloys) and increasing the ductility of the final product. Mechanical properties, bio-corrosion, and crystallographic texture of the material were determined at different stages of the processing. A simultaneous increase in the wire strength, the number of repeated bending until the rupture of the wire, and in the bio-corrosion rate due to drawing has been registered. This phenomenon coincided with a change in the crystallographic texture. It has been shown that the product tensile strength of about 250–300 MPa can be reduced by about 30% due to surgical knots tied on it.

Cold pilgering has been considered as the preferred rolling fabrication technology for difficult-to-deform tubular materials such as high-strength titanium alloy tubes. However, the tooling geometry may induce complex deformation and significantly influence crystallographic texture which is closely related to the dimension assuring and properties tailoring of tube products. In this study, taking high-strength Ti-3Al-2.5V tubes as the case material, the tooling design–related spatial deformation behaviors and crystallographic texture evolution of tube in cold pilgering are focused. A macro-meso scaled computation platform is established by combining the three-dimensional finite element (3D-FE) model with the viscoplastic self-consistent (VPSC) crystal plasticity model to predict both the inhomogeneous macrodeformation and microtexture evolution in cold pilgering. Two basic tooling parameters in pilgering, viz., E1 representing exponent of roller groove curve and mandrel curve and E2 representing exponent of groove clearance, are chosen as the design variables. The cold pilgering under different tooling parameters are simulated and analyzed. The results show that (1) The rolling force decreases with the increase of E1 , while the effect of E2 on the rolling force is not significant, and smaller E1 and larger E2 have advantage for preventing surface defects of the tube product; (2) The E1 of 2.8 and E2 of 2.0 are more conducive to the wall thinning–dominated deformation of tube; (3) Taking the contractile strain ratio (CSR) as an indicator for characterizing crystallographic texture–related mechanical properties, the appropriate values of E1 and E2 for desirable radial texture of tube product are obtained.

This paper presents some results of the influence of severe plastic deformation on the microstructure evolution, grain refinement aspect, and mechanical properties of ultra-low carbon steel. Ti-stabilized experimental IF steel was deformed at a room temperature with unconventional SPD process—dual rolls equal channel extrusion (DRECE). Mechanical properties and structure of ferritic steel in initial state and after selected steps of deformation were investigated. The mechanical properties were determined by static tensile tests carried out at a room temperature and microhardness research. The structural investigations involved using scanning transmission electron microscopy observations, electron back scattered diffraction and measurements of the crystallographic texture. The DRECE process affects the evolution of the structure. The microstructural investigations revealed that the processed strips exhibited a dislocation cell and grain structures with mostly low angle grain boundaries. The electron backscattering diffraction (EBSD) examination showed that the processed microstructure is homogeneous along the strips thickness. The mechanical properties of the DRECE-processed IF steel strips increased with an increase the number of passes.

Titanium and its alloys are the most suitable metallic materials available for the fabrication of medical implants. Their biocompatibility can be improved by the growth of TiO2 nanotubes on their surface by a simple anodization process. This work involved an investigation into the anodization behavior of Ti–35Nb–7Zr–5Ta (TNZT) alloy, focusing on the effect of processing conditions (anodization time and type of electrolyte), previous strain hardening, and crystallographic texture of the substrate. Studies about the growth of TiO2 nanotubes on β-type titanium alloys, as the TNZT alloy, are rare in the literature. The TNZT alloy proved to be an excellent substrate for the growth of TiO2 nanotubes, resulting in threefold longer nanotubes than those obtained on a commercially pure (CP) Ti substrate. Moreover, TiO2 nanowires grew after 6 h of anodization in an organic electrolyte, which could not be achieved using the CP-Ti substrate. Samples with different crystallographic textures displayed similar nanotube morphology and only slight differences in grain length, indicating that grain orientation played only a minor role in the growth kinetics. Lastly, the crystallization of nanotubes at 450 °C did not alter their morphology, but caused complete detachment of the TiO2 nanotubes at 700 °C.

A directionally solidified Ag-Cu eutectic alloy was deformed by rolling to understand the role of heterophase interfaces on the deformation behavior of ultrafine and nanocrystalline face-centred cubic metals. During rolling, the initial 〈220〉 fibre texture was gradually shifted to a Brass type texture for both Ag and Cu phases. More interestingly, a similar path of texture evolution was observed for both the phases at all strain levels. The in-depth transmission electron microscopy analysis revealed that the Ag lamellae deformed primarily by twinning, while the Cu lamellae deformed by twinning and dislocation slip. Furthermore, the special cube-on-cube and twin heterophase interfaces facilitated co-deformation and co-rotation of the adjacent Ag and Cu lamella due to a strong latent hardening effect, which stimulated a similar texture evolution for both phases.

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.

Three distinct layers are present in commercially produced tinplated steels: the top tin layer, the middle Fe-Sn alloy layer, and the bottom steel substrate. The brightness of these steels is inversely proportional to the roughness of the top layer. Substrate steels with recrystallized structure, sharper texture, and cleaner matrix result in flatter Fe-Sn interlayer and subsequently smoother top Sn layer. This in turn gives brighter surface finish.

Rapid thermokinetics associated with laser-based additive manufacturing produces strong bulk crystallographic texture in the printed component. The present study identifies such a bulk texture effect on elastic anisotropy in laser powder bed fused Ti6Al4V by employing an effective bulk modulus elastography technique coupled with ultrasound shear wave velocity measurement at a frequency of 20 MHz inside the material. The combined technique identified significant attenuation of shear velocity from 3322 ± 20.12 to 3240 ± 21.01 m/s at 45$$^\circ$$ ∘ and 90$$^\circ$$ ∘ orientations of shear wave plane with respect to the build plane of printed block of Ti6Al4V. Correspondingly, the reduction in shear modulus from 48.46 ± 0.82 to 46.40 ± 0.88 GPa was obtained at these orientations. Such attenuation is rationalized based on the orientations of $$\alpha ^\prime$$ α ′ crystallographic variants within prior columnar $$\beta$$ β grains in additively manufactured Ti6Al4V.

Electron backscattered diffraction (EBSD) was used to analyze the evolution of microstructure and crystallographic texture during friction stir welding of dissimilar type 2205 duplex stainless steel (DSS) to type S275 low carbon-manganese structural steel. The results of microstructural analyses show that the temperature in the center of stirred zone reached temperatures between Ac1 and Ac3 during welding, resulting in a minor ferrite-to-austenite phase transformation in the S275 steel, and no changes in the fractions of ferrite and austenite in the DSS. Temperatures in the thermomechanically affected and shoulder-affected zones of both materials, in particular toward the root of the weld, did not exceed the Ac1 of S275 steel. The shear generated by the friction between the material and the rotating probe occurred in austenitic/ferritic phase field of the S275 and DSS. In the former, the transformed austenite regions of the microstructure were transformed to acicular ferrite, on cooling, while the dual-phase austenitic/ferritic structure of the latter was retained. Studying the development of crystallographic textures with regard to shear flow lines generated by the probe tool showed the dominance of simple shear components across the whole weld in both materials. The ferrite texture in S275 steel was dominated by D 1, D 2, E, $$ \bar{E} $$ E ¯ , and F, where the fraction of acicular ferrite formed on cooling showed a negligible deviation from the texture for the ideal shear texture components of bcc metals. The ferrite texture in DSS was dominated by D 1, D 2, I, $$ \bar{I} $$ I ¯ , and F, and that of austenite was dominated by the A, $$ \bar{A} $$ A ¯ , B, and $$ \bar{B} $$ B ¯ of the ideal shear texture components for bcc and fcc metals, respectively. While D 1, D 2, and F components of the ideal shear texture are common between the ferrite in S275 steel and that of dual-phase DSS, the preferential partitioning of strain into the ferrite phase of DSS led to the development of I and $$ \bar{I} $$ I ¯ components in DSS, as opposed to E and $$ \bar{E} $$ E ¯ in the S275 steel. The formations of fine and ultrafine equiaxed grains were observed in different regions of both materials that are believed to be due to strain-induced continuous dynamic recrystallization (CDRX) in ferrite of both DSS and S275 steel, and discontinuous dynamic recrystallization (DDRX) in austenite phase of DSS.

The effect of tool geometries on the microstructure and crystallographic texture of 32-mm-thick friction stir-welded AA6082 has been investigated. The use of a tapered probe tool results in a significant variation in the grain size from the top to the base of the nugget, whereas parallel probe tools produce a uniform grain size throughout the nugget. The grain size in the nugget reflects the amount of deformation experienced and the speed of deformation expressed in terms of strain rate. An approach is proposed to calculate the strain rate during FSW of aluminum for which values between 217 and 362 s−1 were obtained. The strain rate can be either uniform or varied through the joint thickness based on the type of tool used. The tapered tool produces a variation of the strain rate, whilst the parallel tool has a uniform strain rate throughout, which can explain the obtained grain structure in each case. The tool geometries also influenced texture development with the tapered tool producing a tilt of the local shear reference frame by an angle to the normal direction equal to the taper angle.

Plastic deformation of metallic materials is an inherently anisotropic process as a result of the presence of preferential orientations in their crystallographic texture. Crystal plasticity modeling, which allows simulating the response of polycrystal aggregates taking into account their texture and other microstructural parameters, has been extensively used to predict this behavior. In this work, crystal plasticity models are used to deal with the opposite problem: given a desired behavior, determine how to modify a texture to approximate this behavior in the most efficient way. This goal can be expressed as an optimization problem, in which the objective is to find the texture with the best formability properties among all the possible ones. An incremental optimization method, based on the gradient descent algorithm, has been developed and applied to different initial textures corresponding to typical steel and aluminum sheet products. According to expectations, the textures found present a stronger $$\gamma $$ γ fiber component. Moreover, the method sets the basis for the development of more complicated optimization schemes directed toward optimizing specific materials and forming processes.

Since the production of tinplate with non-earing properties is difficult, especially when it is produced via the double-reduction process, the optimal degree of second cold reduction is particularly important for achieving desirable drawing properties. The evolution of texture and the earing propensity of double-reduction tinplate with different extents of second reduction were investigated in this study. Optical microscopy and scanning electron microscopy were used to observe the changes in the microstructure at various extents of reduction. Two common testing methods, X-ray diffraction (XRD) and electron backscatter diffraction, were used to investigate the texture of the specimens, which revealed the effects of deformation percentage on the final texture development and the change in the grain boundary. The earing rate was determined via earing tests involving measurement of the height of any ear. The results obtained from both XRD analyses and earing tests revealed the same ideal value for the second cold reduction on the basis of the relationship between crystallographic texture and the degree of earing.

A novel low-carbon micro-alloyed steel has been developed with ultrahigh strength (UTS ~ 1700 MPa), satisfactory ductility (total elongation ~ 13%) and impact toughness (25 J/cm2 at − 40 °C) for light-weight applications in automobile, aerospace and defence sectors. The effect of finish rolling temperatures (850–750 °C) and cooling rate (air cooling versus water quenching) on the evolution of microstructure and crystallographic texture and finally on the mechanical properties of thermo-mechanically controlled processed steel has been studied. A refinement in mixed microstructure comprised of granular/lower bainite and lath/plate martensite and an intensification of Goss and rotated Goss texture components were found with the decrease in finish rolling temperature and increase in cooling rate. Interaction of fine-scale carbide/carbonitride precipitates of Nb and Ti with the dislocation substructure present within bainite and martensite contributed significant precipitation strengthening to the steel.

In this paper, the microstructure and crystallographic texture of pure Ti thin walls generated by Additive Manufacturing based on Laser Cladding (AMLC) are analyzed in depth. From the results obtained, it is possible to better understand the AMLC process of pure titanium. The microstructure observed in the samples consists of large elongated columnar prior β grains which have grown epitaxially from the substrate to the top, in parallel to the building direction. Within the prior β grains, α-Ti lamellae and lamellar colonies are the result of cooling from above the β-transus temperature. This transformation follows the Burgers relationship and the result is a basket-weave microstructure with a strong crystallographic texture. Finally, a thermal treatment is proposed to transform the microstructure of the as-deposited samples into an equiaxed microstructure of α-Ti grains.

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.

The crystallographic texture of γ′-Fe4N in compound layer and its influences on the tribological properties of nitrided steel 38CrMoAl are investigated in the study. The preferred orientation of (200)γ′ is produced by low-temperature nitriding in atmosphere with low nitrogen–hydrogen ratio and increases with the nitriding time. The preferred orientation of (220)γ′ appears after 72 h cyclic nitriding. The orientation relationships (0001)e//(101)α′ and [110]e//[111]α′, (111)γ′//(0001)e and $$\left[ {011} \right]_{{\gamma^{\prime } }} //\left[ {1\overline{2} 10} \right]_{\varepsilon }$$ , (200)γ′//(110)α′ and [011]γ′//[111]α′, as well as $$\left( {1\overline{1} 03} \right)_{\varepsilon } //\left( {220} \right)_{{\gamma^{\prime } }}$$ and $$\left[ {0100} \right]_{\varepsilon } //\left[ {1\overline{1} 0} \right]_{{\gamma^{\prime } }}$$ are established by first-principles method. The misfit of interatomic distance (δ), determining the phase transition resistance, is calculated. Accordingly, two reaction pathways during nitriding, α′→γ′ and α′→e→γ′, are assumed, which determines the preferred orientations of γ′-Fe4N. Results of wear tests demonstrate that the specimen with preferred orientation of (200)γ′ exhibits lower frictional coefficient and lower wear rate in comparison with the specimen with (220)γ′ preferred orientation. (111)γ′ texture usually relates to the lower frictional coefficient but higher wear rate due to the main slip system parallel to the sliding plane. Therefore, the (200)γ′ preferred orientation has a positive significance in improving the wear properties of steels.

BCC alloys commonly tend to develop strong fibre textures and often represent as isointensity diagrams in φ 1 sections or by fibre diagrams. Alpha fibre in bcc steels is generally characterised by 〈110〉 crystallographic axis parallel to the rolling direction. The objective of present research is to correlate carbon content, carbide dispersion, rolling reduction, Euler angles (ϕ) (when φ 1 = 0° and φ 2 = 45° along alpha fibre) and the resulting alpha fibre texture orientation intensity. In the present research, Bayesian neural computation has been employed to correlate these and compare with the existing feed-forward neural network model comprehensively. Excellent match to the measured texture data within the bounding box of texture training data set has been already predicted through the feed-forward neural network model by other researchers. Feed-forward neural network prediction outside the bounds of training texture data showed deviations from the expected values. Currently, Bayesian computation has been similarly applied to confirm that the predictions are reasonable in the context of basic metallurgical principles, and matched better outside the bounds of training texture data set than the reported feed-forward neural network. Bayesian computation puts error bars on predicted values and allows significance of each individual parameters to be estimated. Additionally, it is also possible by Bayesian computation to estimate the isolated influence of particular variable such as carbon concentration, which exactly cannot in practice be varied independently. This shows the ability of the Bayesian neural network to examine the new phenomenon in situations where the data cannot be accessed through experiments.

The severity of the formation of fissures (also known as splitting or delamination) on the fracture surface of Charpy impact-tested samples of a low-carbon steel has been found to increase with the decrease in finish rolling temperature [1093 K to 923 K (820 °C to 650 °C)]. Combined scanning electron microscopy and electron back-scattered diffraction study revealed that crystallographic texture was the prime factor responsible for the fissure formation. Through-thickness texture band composed of cube [Normal Direction (ND)║〈001〉] and gamma [ND║〈111〉] orientations developed during the inter-critical rolling treatment. Strain incompatibility between these two texture bands causes fissure cracking on the main fracture plane. A new approach based on the angle between {001} planes of neighboring crystals has been employed in order to estimate the ‘effective grain size,’ which is used to determine the cleavage fracture stress on different planes of a sample. The severity of fissure formation was found to be directly related to the difference in cleavage fracture stress between the ‘main fracture plane’ and ‘fissure plane.’ Clustering of ferrite grains having cube texture promoted the fissure crack propagation along the transverse ‘fissure plane,’ by increasing the ‘effective grain size’ and decreasing the cleavage fracture stress on that plane.

In the present study, Nb-stabilized ferritic stainless steel was prepared with annealing (430-A) and without annealing (430-NA) annealing, and the microstructure of the resulting samples was examined. The steel was then subjected to cold rolling and isothermal annealing in order to analyze its recrystallization kinetics and texture evolution. Microstructural characterization was performed by scanning and transmission electron microscopies. Recrystallization kinetics were evaluated by measuring the microhardness of the samples, and analyzing their kernel average misorientation and grain orientation spread via electron backscatter diffraction. The Avrami exponent data revealed that one-dimensional grain growth occurred owing to the migration of high-angle grain boundaries. The mean activation energies for recrystallization for 430-NA and 430-A was found to be 365 and 419 kJ mol−1, respectively. The recrystallization texture was influenced by oriented nucleation and selected growth mechanisms, as well as by the Nb carbonitride distribution and grain boundary energy. The recrystallized and growing grains with the {554}〈225〉 orientation showed a dimensional advantage over the other recrystallized components. The coincident site lattice boundaries were attributed to the progression of recrystallization since the CSL numeric fraction increased as the temperature increased. The {554}〈225〉 component was associated with the ∑19a boundary, which exerted a significant control on the selective growth during the recrystallization.

The hot deformation behavior of 2101 grade lean duplex stainless steel (DSS, containing similar to 5 wt pct Mn, similar to 0.2 wt pct N, and similar to 1.4 wt pct Ni) and associated microstructural changes within delta-ferrite and austenite (gamma) phases were investigated by hot-compression testing in a GLEEBLE 3500 simulator over a range of deformation temperatures, T (def) 1073 K to 1373 K (800 A degrees C to 1100 A degrees C)], and applied strains, epsilon (0.25 to 0.80), at a constant true strain rate of 1/s. The microstructural softening inside gamma was dictated by discontinuous dynamic recrystallization (DDRX) at a higher T (def) 1273 K to 1373 K (1000 A degrees C to 1100 A degrees C)], while the same was dictated by continuous dynamic recrystallization (CDRX) at a lower T (def) (1173 K (900 A degrees C)]. Dynamic recovery (DRV) and CDRX dominated the softening inside delta-ferrite at T (def) 1173 K (900 A degrees C). The dynamic recrystallization (DRX) inside delta and gamma could not take place upon deformation at 1073 K (800 A degrees C). The average flow stress level increased 2 to 3 times as the T (def) dropped from 1273 to 1173 K (1000 A degrees C to 900 A degrees C) and finally to 1073 K (800 A degrees C). The average microhardness values taken from delta-ferrite and gamma regions of the deformed samples showed a different trend. At T (def) of 1373 K (1100 A degrees C), microhardness decreased with the increase in strain, while at T (def) of 1173 K (900 A degrees C), microhardness increased with the increase in strain. The microstructural changes and hardness variation within individual phases of hot-deformed samples are explained in view of the chemical composition of the steel and deformation parameters (T (def) and epsilon). (C) The Minerals, Metals & Materials Society and ASM International 2016

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.

Electrochemical hydrogen charging and permeation techniques were used to characterize hydrogen distribution, trapping, and diffusion in X60 and X60 sour service (X60SS) pipeline steels. The results obtained contribute to better understanding of hydrogen-induced cracking (HIC). SEM observations illustrated that all HIC cracks were formed at the center of cross section in the X60 steel after 3-h hydrogen charging and length of cracks increased with charging time. No HIC cracks were recorded at the cross section of X60SS steel after the same charging for different durations. Hydrogen permeation tests showed that the density of reversible hydrogen traps was lower at the center of cross section in the X60SS steel compared to the X60 one, and this is considered as one of the main reasons for high resistance of X60SS steel to HIC. EBSD orientation imaging results proved that the accumulation of ||ND-oriented grains at the center of the cross section in the X60SS steel was high. This is also considered as another reason for higher resistance of this steel to HIC. Finally, the center segregation zone with higher hardness value in the X60 steel was more pronounced than in the X60SS steel which made the X60 steel susceptible to HIC cracking.

A cross-rolled plate of the industrially important titanium alloy, Ti-6Al-4V, has been microstructurally and mechanically characterised using a range of different experimental techniques. The microstructure of the material has been studied using backscatter electron (BSE) microscopy and electron backscatter diffraction (EBSD), with the crystallographic orientation data from the EBSD used to reconstruct the orientation distribution function of the dominant α phase. The mechanical behaviour of the material has been investigated at quasi-static and high strain rates in the three orthogonal material orientations in both tension and compression. A novel in situ optical measurement technique has been used to measure the geometry of the specimens during both quasi-static and high strain rate mechanical testing, improving the accuracy of the mechanical testing results and providing unprecedented information about the evolving geometries of the specimens. The macroscopic stress–strain response and the evolution of specimen cross-sectional profiles have been qualitatively linked to the macroscopic crystallographic texture in the plate.

In this research, ultrafine-grained sheets of aluminum matrix composite (Al-Al2O3-B4C) were produced by accumulative roll bonding ARB technique. As-received, ultrafine-grained aluminum composite sheets were joined by friction-stir welding. The microstructure, crystallographic texture, and Vickers hardness in the weld zones were investigated. Electron backscattered diffraction results revealed occurrence of dynamic recrystallization and demonstrated existence of different grain orientations within the weld nugget. Produced composite plates illustrated rotated cubic texture. Moreover, in the nugget, a well-recrystallized grain structure having characteristic strong shear texture component finally developed. However, the texture result in the heat-affected zone illustrated rotated cubic and Goss components that related to the effect of heat input. Friction-stir welding refined the grain size in the weld zone. The hardness also improved with the peak hardness being observed towards the advancing stir welding side.

Friction-stir processing (FSP) has been proven as a successful method for the grain refinement of high-strength aluminum alloys. The most important attributes of this process are the fine-grain microstructure and characteristic texture, which impart suitable properties in the as-processed material. In the current work, FSP of the precipitation-hardenable aluminum alloy 2219 has been carried out and the consequent evolution of microstructure and texture has been studied. The as-processed materials were characterized using electron back-scattered diffraction, x-ray diffraction, and electron probe microanalysis. Onion-ring formation was observed in the nugget zone, which has been found to be related to the precipitation response and crystallographic texture of the alloy. Texture development in the alloy has been attributed to the combined effect of shear deformation and dynamic recrystallization. The texture was found heterogeneous even within the nugget zone. A microtexture analysis revealed the dominance of shear texture components, with C component at the top of nugget zone and the B and A(2)* components in the middle and bottom. The bulk texture measurement in the nugget zone revealed a dominant C component. The development of a weaker texture along with the presence of some large particles in the nugget zone indicates particle-stimulated nucleation as the dominant nucleation mechanism during FSP. Grain growth follows the Burke and Turnbull mechanism and geometrical coalescence.

This paper reports a study on reducing the yield strength of Cu ribbon wire used for Si solar cell interconnections in solar panels. Low yield strength Cu core should be used as the interconnector ribbon to minimize the fracture of Si solar cells during the tabbing process. We lowered the yield strength of Cu ribbon by controlling the crystallographic texture without increasing the annealing time and temperature. The crystallographic texture was controlled by lubrication in a cold rolling process. The crystallographic texture was observed by scanning electron microscopy with electron back scattered diffraction. A tensile test was performed for the comparison of the mechanical properties of Cu with and without lubrication. The average yield strength was 91.2 MPa with lubrication whereas the yield strength was 99.6 MPa without lubrication. The lower value of the lubricated samples seemed to be caused by the higher cube texture intensity than that of the samples without lubrication.

Bobbin tool friction-stir welding was used to join 3.2-mm-thick AA2198. The textural results show that four sub zones are formed vertically in the stirred zone. The materials in upper and lower two zones underwent negative and positive shears, respectively; they are uniformly recognized as dominate C and minor A simple shear components.

In this work, half channel angular extrusion, a recently developed severe plastic deformation (SPD) process, applied to AZ31 Mg alloy. Effects of the initial microstructure of AZ31 alloy on the microstructural development such as the grain refinement and texture evolution during the half channel angular extrusion (HCAE) has been studied. It was found that the grains of the AZ31 alloys can be refined remarkably by single pass of HCAE than other SPD techniques and not only the grain refinement but also the deformation induced textures result in a noticeable enhancement of mechanical properties.

Although the texture of Ti alloys is currently evaluated by the pole figure, it can only provide incomplete and qualitative information. In this investigation, the textures of Ti-3Al-2.5V tubing were studied to seek for an appropriate method for evaluating Ti tubing texture. The texture measurement was performed by thinning the tubing chemically into foils and flattening them, followed by x-ray diffraction analysis. A Bruker D8 Advance texture goniometer with Cu Kα radiation was employed for measuring the {0002}, {10-10}, {10-12}, {11-20} and {10-13} incomplete pole figures using the Schultz reflection technique. Based on the pole data, the crystallite orientation distribution function (ODF) was synthesized using TexEval V2.5 software, Bruker AXS GmbH. The texture strengths of the three specimens were compared using pole figures and ODF. It is found that it gives rise to a large error in the texture strength using the pole figure to evaluate texture. The orientation densities of the maxima in ODF and the tilt angle of their basal poles from the normal toward the tangential direction can describe the tubing texture accurately, which can evaluate the tubing mechanical properties. Subsequently, ODF can be used to predict the mechanical properties of batches of tubing.

Nowadays, there are limited referenced data on the hot deformation of twinning induced plasticity (TWIP) steels, particularly on the crystallographic preferred orientation (crystallographic texture). It is well know that texture is one of the most important factors affecting sheet metal forming performance. The aim of this research work is to determine the influence of microalloying elements on the microstructure and texture of high-Mn austenitic TWIP steels deformed under uniaxial hot-tensile conditions. For this purpose, one non-microalloyed and other single microalloyed with Ti, V and Mo TWIP steels were melted in an induction furnace and cast into metal and sand molds. Samples with average austenitic grain size between 400 and 2000 µm were deformed in the temperature range between 800 and 900 °C at a constant true strain rate of 10-3 s-1. The evolution of the microstructure and texture near to the fracture tip were characterized using electron back-scattering diffraction (EBSD) technique. The results show that the TWIP steels microalloyed with V and Mo and the non-microalloyed one, solidified in metal mold, exhibit dynamically recrystallized grains oriented in the [012] preferential direction, which was corroborated by local misorientation measurements, indicating low dislocation density. On the other hand, most TWIP steels solidified in sand molds do not show dynamically recrystallized grains, having the largest austenitic grains oriented in the [001]/[101] preferred directions. In general, weak textural Cube {001} combined with fiber, namely γ-fiber, spread from E {111} to Y {111} as major texture components were detected.

We present a detailed characterization of crystallographic texture and in-grain morphology in high purity Tantalum (Ta) during cross-rolling. A Ta disk with random initial texture was rolled to a total reduction of 50 pct in four equal steps, with the disk being rotated by 90 deg around the normal direction (ND) after every rolling step. Samples were cut along ND and were characterized using electron backscatter diffraction (EBSD), before and after the final deformation. Through-thickness texture heterogeneity was observed in the deformed disk, with an increase in 〈111〉 and 〈100〉 volume fraction parallel to ND from the surface toward the disk mid-section. The deformed texture of the mid-section of the disk (i.e., experiencing limited shear) was found to have a strong γ-fiber and a weak α-fiber with presence of only {100} 〈110〉 texture component. From the grain-scale EBSD study, the deformed grain morphology was found to be one of the three major types: (a) un-fragmented, (b) fragmented-mottled, and (c) fragmented-banded or elongated deformation bands. The un-fragmented grains had 〈111〉 parallel to ND, with 〈110〉 parallel to the rolling direction or the transverse direction. The fragmented-mottled grains had multiple sub-grain orientations. The two major bands in the fragmented-banded grains had its 〈100〉 and 〈111〉 parallel to ND. In addition, they shared a common 〈110〉 with a misorientation of 30 deg. Through our knowledge of the known stable components formed during rolling of Ta, it was feasible to explain the orientations of such un-fragmented and fragmented-banded grains.

A galvanizing simulator was used to determine the effect of galvanizing bath antimony (Sb) content, substrate surface roughness, and cooling rate on the microstructural development of metallic zinc coatings. Substrate surface roughness was varied through the use of relatively rough hot-rolled and relatively smooth bright-rolled steels, cooling rates were varied from 0.1 to 10 K/s, and bulk bath Sb levels were varied from 0 to 0.1 wt pct. In general, it was found that increasing bath Sb content resulted in coatings with a larger grain size and strongly promoted the development of coatings with the close-packed {0002} basal plane parallel to the substrate surface. Increasing substrate surface roughness tended to decrease the coating grain size and promoted a more random coating crystallographic texture, except in the case of the highest Sb content bath (0.1 wt pct Sb), where substrate roughness had no significant effect on grain size except at higher cooling rates (10 K/s). Increased cooling rates tended to decrease the coating grain size and promote the {0002} basal orientation. Calculations showed that increasing the bath Sb content from 0 to 0.1 wt pct Sb increased the dendrite tip growth velocity from 0.06 to 0.11 cm/s by decreasing the solid–liquid interface surface energy from 0.77 to 0.45 J/m2. Increased dendrite tip velocity only partially explains the formation of larger zinc grains at higher Sb levels. It was also found that the classic nucleation theory cannot completely explain the present experimental observations, particularly the effect of increasing the bath Sb, where the classical theory predicts increased nucleation and a finer grain size. In this case, the “poisoning” theory of nucleation sites by segregated Sb may provide a partial explanation. However, any analysis is greatly hampered by the lack of fundamental thermodynamic information such as partition coefficients and surface energies and by a lack of fundamental structural studies. Overall, it was concluded that the fundamental mechanisms behind the microstructural development of solidified metallic zinc coatings have yet to be completely elucidated and require further investigation.

In this paper, we investigate the structural evolution of a fine-grained Ni3Al (Zr, B) interme-tallic-based alloy during cold rolling. X-ray diffraction (XRD) and field emission gun (FEG) scanning electron microscopy (SEM) were used with an electron backscattered diffraction (EBSD) system to analyse changes in the ordering, microstructure, microtexture and lattice strain during plastic deformation of the investigated alloy. The results showed that the Ni3Al (Zr, B) intermetallic-based alloy underwent extensive microstructural and ordering changes upon plastic deformation. This transformation was facilitated by a change in the rolling texture from that of a pure metal to that of an alloy. This textural transition could be attributed to the localisation of the plastic deformation in the form of intense shearing. The occurrence of mechanical twinning was not directly confirmed by the experimental results; therefore, the reordering transition could also have affected the occurrence of the shear banding. The lattice strain was also analysed using the EBSD method (using local misorientation or pattern quality approaches) and microhardness measurements, which showed that the observed structural transformation was also facilitated by an accommodation process that produced a partial release of stored energy.