Rotated Cube Texture Research Articles

Graded microstructure and texture in ultrafine grained multi-layered immiscible bimetallic system

In this investigation we report the formation of a graded microstructure in copper/tantalum ultrafine grained (UFG) multi-layered composite fabricated by cross accumulative roll bonding (CARB) process at high temperatures. The microstructure, micro-texture and bulk texture evolution in the copper/tantalum composite was established. A gradient microstructure develops along the thickness of the specimen during the CARB process. The fragmentation of tantalum in between copper layers and the grain refinement with evolving passes has been explained. The deformed copper layers show rotated cube texture and deformed tantalum layers show cube texture with γ-fibre. The overall texture of copper/tantalum composite weakens after the process of ARB; copper undergoing texture randomization post annealing. The crucial role of interfaces on the evolution of texture is demonstrated. The microstructural gradient in the specimen possess equiaxed, lamellar as well as large deformed grains with tantalum's grain size being in the scale of 200 nm. The correlation of microstructural gradient with orientation relationship (OR) between copper and tantalum layers was studied, confirming higher misorientation in OR at regions under high strain. Dynamic recrystallization taking place at the copper/tantalum interface has been elaborated with the aid of microtexture analysis.

Deformation Behavior and Evolution of Austenite Microstructure and Texture During Hot Compression of 5CrNiMoV Steel

Deformation behaviour of 5CrNiMoV steel was investigated at temperature 830–1230 °C and strain rate 0.001–10 s−1. The flow curves were analyzed to illuminate the deformation characteristics. Comprehensive austenite microstructural investigation was carried out using optical microscope for deformed samples. It was found that discontinuous dynamic recrystallization mechanism played a leading part in the nucleation of dynamic recrystallization (DRX) nuclei and growth of DRX grains, and that the austenite grain size increased with deformation temperature, while a larger strain rate was conducive to grain refinement for the quickly generated strain storage-energy favorable for higher DRX nucleation rate. The parent austenite texture evolution and typical martensitic transformation texture for some deformed samples were characterized using electron backscattering diffraction technique and the software of the reconstruction of parent austenite. It was found that increasing temperature contributed to the increase of its maximum of random distribution (MRD) and the strength of rotated Cube texture component, which was probably for the behavior DRX and growth of DRX grains during the hot deformation. The rotated Cube was weakened with the strain rate rising, while the main texture component did not change significantly, which was due to the increase in number of active slip systems and grain fragmentation. Besides, the martensitic transformation texture was related to the parent texture for the variant selection.

Graded Microstructure and Texture in Ultrafine Grained Multi-Layered Immiscible Bimetallic System

In this investigation we report the formation of a graded microstructure in copper/tantalum ultrafine grained (UFG) multi-layered composite fabricated by cross accumulative roll bonding (CARB) process at high temperatures. The gradient microstructure develops as a consequence of the strain gradient present along the thickness of the specimen during the CARB process. The correlation of strain gradient with the microstructure, micro-texture and bulk texture in copper/tantalum composite was established. The fragmentation of tantalum in between copper layers and the grain refinement with evolving passes has been explained. The deformed copper layers show rotated cube texture and deformed tantalum layers show cube texture with γ- fibre. The overall texture of copper/tantalum composite weakens after the process of ARB; copper undergoing texture randomization. The crucial role of interfaces on the evolution of texture is demonstrated. The effect of strain on orientation relationship (OR) between copper and tantalum layers was studied, confirming higher misorientation in OR at regions under high strain. Dynamic recrystallization taking place at the copper/tantalum interface has been elaborated with the aid of microtexture analysis.

Different behavior of alpha and beta phases in a Low Stacking Fault Energy copper alloy under severe plastic deformation

In this research, two phase brass alloy as one of the most important copper base alloys was processed by equal channel angular pressing as a severe plastic deformation process. The process was performed at 350 °C in route C up to 6 passes. Microstructural study showed that discontinuous recrystallization initiated at the first pass in the alpha phase. Recrystallization fraction enhanced by increasing the amount of strain and grain size decreased to less than one micron after the fifth and sixth passes. Investigations of beta phase showed that recrystallization in this phase began after the third pass and enhanced with increasing the number of passes. Separate investigation of macro-texture for two phases of alpha and beta well proved the different deformation behavior in both phases. Furthermore, it was observed that Goss, Rotated Goss and Rotated cube texture components were dominant for alpha phase, and cube and {112} <111> texture components were dominant for beta phase that had a direct impact on the results of mechanical properties. Micro-hardness and tensile test were used in order to study the mechanical properties of the alloy. The results indicated a massive increase in micro-hardness and tensile strength after the process. Also, total elongation in the processed specimens was higher than expectations in a manner that after the final pass, it reached more than 80% which was only approximately 35% less than the primary anneal specimen.

Effect of the hot rolling on Goss development and magnetic induction in an advanced soft magnetic Fe–27%Co alloy

Abstract This paper shows a complete study about the characterization of the texture and the microstructure evolution of an industrial thermo-mechanical processing aiming to develop an advanced soft magnetic Fe–27%Co material with a sharp Goss texture. Thanks to its intrinsic magnetic properties, such an alloy should be able to get a place in the market of aircraft transportation transformers. It appears that the development of a highly Goss textured Fe–27%Co alloy could be achieved by optimizing the intensity of the Goss and rotated Cube texture during hot rolling using an adequate thermo-mechanical processing, namely finishing hot rolling in the ferritic phase.

Effect of the Deformation Amount on the Microstructure and Tensile Properties of 304 Stainless Steel with 2 wt% Al Content by Cold Rolling

The microstructure evolution during cold rolling and mechanical properties after solution treatment of 304 stainless steel with 2 wt% Al are investigated and the tensile properties of the steels are also tested. The results show that the steel consists of ferrite and austenite phases and small amounts of granular precipitates of Al4C3 and AlN, and the content of ferrite decreases gradually with increase of the deformation. For deformations of 30%, 50%, and 70%, the average grain sizes of the samples are 10.23, 8.66, and 7.13 μm, respectively. After solution treatment grain refinement is obvious for the &lt;101&gt; orientation and a large number of annealing twin grain boundaries are observed in the austenite phase. The sample with 50% deformation contains the highest volume fraction of recrystallized grains. The {001}&lt;100&gt; cube texture and {001}&lt;110&gt; rotated cube texture are present in the ferrite and austenite phases. The yield strength of the steel increases gradually with the increase in the cold rolling reduction; meanwhile the elongations are all above 40%. Especially for the sample with the reduction of 70%, the yield strength of the solution‐treated specimen is 417 MPa, and the elongation is ≈50%.

Effect of cross cold rolling and annealing on microstructure and texture in pure nickel

Abstract The microstructure and texture in pure nickel were investigated during multi-step cross cold rolling (CCR) and subsequent annealing. It was found that the deformation texture in the CCR nickel was dominated by Brass and rotated Brass about normal direction (ND) (Bs ND ) texture components, along with marginal cube textures. The resulted deformation textures had a significant effect on the recrystallization behavior. Annealing of the CCR nickel at 550°C for 1 h led to the formation of dominant &lt;012&gt; // ND fiber accompanied by minor rotated cube textures, rather than strong cube texture. Increasing the annealing temperature up to 800°C resulted in further enhancement of &lt;012&gt; // ND fiber textures. The possible reasons for recrystallization behavior in annealed CCR sample were discussed based on in-situ annealing experiments from two aspects of oriented nucleation and oriented growth theories.

Element partitioning and electron backscatter diffraction analysis from feeding wire to as-deposited microstructure of wire and arc additive manufacturing with super duplex stainless steel

The redistribution of alloying elements and the crystallographic characterizations in wire and arc additive manufactured (WAAM) super duplex stainless steel (SDSS) was investigated from the wire to the final as-deposited structure. The results showed that elemental partitioning between austenite and ferrite was suppressed in the last layer and the solidified droplet. The high Ni content but low Cr and N contents in the initial state of the intragranular austenite (IGA) confirmed the predominance of the chromium nitrides acted as the nucleation sites. Gathering of nitrogen was found more distinct in the coarsening IGA, Widmanstätten austenite (WA) than the grain boundary austenite (GBA). The columnar epitaxial ferrite presented a strong <001> texture in the deposition direction, while the <001> and <101> orientations was found in the austenite. Random orientations of the intragranular secondary austenite was revealed. The Rotated Cube texture of the austenite grains were consumed by the “recrystallization” textures (Brass, Rotated Brass, Cu, R, E, and F) caused by the austenite reformation. The low-angle interphase boundaries between austenite and ferrite were predominated in the as-deposited wall, and, at which, the K–S orientation took the crucial part. A Taylor factor analysis revealed that through fabrication via additive process, the austenite became oriented “harder” and contributed most to good mechanical properties. The textured microstructure contributed about a 2.6% higher engineering strain in the Z direction and a 27.8 MPa higher yield strength in the X direction.

Microstructure and texture development in Ti-15V-3Cr-3Sn-3Al alloy – Possible role of strain path

In the present investigation, evolution of microstructure and texture was studied for a β titanium alloy during cold rolling (unidirectional rolling (UDR) and cross rolling (multi-step cross rolling (MSCR) and two step cross rolling). For both UDR and MSCR of initially hot rolled alloy consisting of elongated and equiaxed grain structure, the occurrence of shear bands inside the grains was the main feature of the microstructure. The density of these shear bands was dependent on the cold rolling reduction and strain path and was found to be orientation dependent. Shear bands preferentially occurred in γ-fiber (normal direction (ND)//〈111〉) oriented grains. The regions with shear bands had higher hardness than the regions without shear bands, and {111}〈112〉 component of the γ-fiber was found to be more susceptible to formation of shear bands. The orientation dependence of these shear bands was analyzed within the framework of Dillamore's plastic instability criterion. During UDR, strong α and γ-fibers were observed after highest strain (ε = 1.6), while strong rotated cube ({100}〈110〉) texture developed after MSCR at highest strain (ε = 1.6). The volume fraction of both α and γ fibers gradually increased with the increase in cold rolling reduction during UDR. For MSCR, the rotated cube component gradually increased with increase in cold rolling reduction. In solution annealed β-Ti alloy with equiaxed grain structure, α and γ fibers were formed after highest strain (ε = 1.6) during UDR. However, due to large grain size, both α and γ fibers were discontinuous. The texture development was found to be more strongly dependent on the strain path than the initial microstructure during cold rolling.

Microstructural characterization of Ni-based superalloy 625 clad welded on a 9% Ni steel pipe by plasma powder transferred arc

The 9% Ni steel was for the first time cladded with Ni-based superalloy 625 by plasma powder transferred arc welding (PPTAW), and the clad microstructure was evaluated for application in the oil and gas industry. The microstructure of the clad was studied using scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, electron backscatter diffraction, X-ray diffraction texture analysis and Vickers microhardness. In the transition zone (TZ), an abrupt variation in chemical composition, type-II boundary, macrosegregations, and intense epitaxial nucleation occurred. The crystallographic texture continuously increased from the TZ (randomly) to the clad surface with moderated rotated cube texture component. The clad showed low residual strain and high fraction of high-angle grain boundary. The segregation of Mo and Nb during the clad solidification generated interdendritic precipitates (MC-type carbide and Laves phase), and no hot cracks were found. The microhardness showed a peak in the heat- affected zone and continuously dropped from the TZ to the clad surface. The PPTAW one-layer clad reached the DNV-OS-F101 standards and has been approved for use in the oil and gas industry.

Columnar grain growth during annealing prior to cold rolling of non-oriented electrical steels

The present research reports the microstructural factors that favor the development of columnar grains during annealing prior to cold rolling (APCR). Results show that decarburization of steel has a strong effect on phase transformations, grain structure and crystallographic texture. Annealing at 850 °C (two-phase field) promotes the development of columnar-grained microstructures with orientations close to the ideal cube texture. Higher annealing temperatures within the intercritical region, results in a mixture of columnar + equiaxial grains (875 °C) or completely equiaxial-grained microstructures (900 °C). Annealing at temperatures within the single ferrite (700 °C, 750 °C) or austenite (950 °C, 1050 °C) phase fields does not promote the development of columnar grains. In these cases, annealing promotes the development of equiaxial grains with rotated cube texture and orientations along the γ-fibre. Changes in texture produced by APCR are consistent with the Bain and Kurdjumov-Sachs correspondence relationships and occur according to oriented nucleation and selective growth mechanisms depending on the characteristics of decarburization.

Microstructure and mechanical anisotropy of CoCrW alloy processed by selective laser melting

We have investigated the correlation between the microstructure and mechanical anisotropy of biomedical CoCrW alloy processed by selective laser melting (SLM). A phase analysis revealed that the as-SLM CoCrW alloy consisted of mostly the γ-fcc phase and little ε-hcp phase. The as-SLM CoCrW microstructure featured the rotated cube texture, a strong <100> texture along the building direction (BD) and a weaker <110> texture along the front direction. To investigate the mechanical anisotropy, the external loading was applied either perpendicular or parallel to the BD (i.e., horizontal loading (⊥BD) or vertical loading (//BD), respectively). The rotated cube texture leads to a higher elastic modulus (~ 2.4 times), plastic flow stress, and microhardness in the horizontal loading. Macroscopic plastic anisotropy was elucidated by the Taylor factor analysis of polycrystalline aggregate. Strain-induced martensite transformation (SIMT) occurring in the horizontal loading (ef = 6.9%) is responsible for significantly reduced elongation to fracture compared to the vertical loading (ef = 32.8%). In the fatigue crack growth experiment, the threshold stress intensity range in the vertical loading is ~ 32% higher compared to the horizontal loading, leading to a retarded fatigue crack growth rate. A vertically elongated columnar granular structure due to the epitaxial grain growth along the BD results in anisotropic behavior of the fatigue crack growth.

Evaluation of dynamic development of grain structure during friction stir welding of pure copper using a quasi in situ method

By employing a quasi in situ method, we investigated the dynamic evolution of the grain structure considering the material flow, strain, and strain rate in the friction stir welding of pure copper. The tool ‘stop action’ and rapid cooling were employed and a brass foil was used as a marker to show the material flow path. The grain structure along the material flow path was characterised using electron backscatter diffraction. Static recrystallization occurs for the work-hardened base material in the preheating stage in front of the tool. In the acceleration flow stage, grains are significantly refined by plastic deformation, discontinuous dynamic recrystallization, annealing twinning during the strain-induced boundary migration and slight continuous dynamic recrystallization. In the deceleration flow stage, due to a strain reversal, the grain first coarsens, and is thereafter refined again. Finally, the hot-deformed material in the shoulder-affected zone is ‘frozen’ directly whereas that in the probe-affected zone undergoes significant annealing; thus, the recrystallized microstructure and 45°-rotated cube texture are obtained in the probe-affected zone.

Texture variations and mechanical properties of aluminum during severe plastic deformation and friction stir processing with SiC nanoparticles

Annealed 1050-aluminum sheets were severely deformed at the strain magnitude of 2.32 through constrained groove pressing (CGP) process. Texture variations and mechanical properties were investigated during CGP and subsequent friction stir processing (FSP) with different volume fractions of SiC nanoparticles. The results revealed that the predominant texture component in the annealed aluminum was {001}〈100〉 cube texture. After CGP, deformed and shear texture components developed while the cube texture was partially remained. In the specimen undergone FSP without nanoparticles, {001}〈110〉 rotated cube and nearly {001}〈110〉 shear texture component C were mainly pronounced, which was indicative of shear deformation of material in the stir zone. Orientation distribution function analysis from the stir zone demonstrated variations in the texture development with the incorporation of SiC nanoparticles. An increase in the fraction of nanoparticles changed the grain orientation in such a way that the {001}〈110〉 shear texture component C gradually developed from the rotated cube texture. However, the overall texture intensity became weaker by increasing the fraction of SiC nanoparticles due to the activation of particle stimulated nucleation mechanism forming randomly oriented grains. The incorporation of SiC nanoparticles in the stir zone also enhanced the yield strength, Young's modulus, and hardness of the stir zone without considerable reduction in the elongation. In such situation, Orowan strengthening was suggested as a dominant mechanism involved.

The effect of inhomogeneous microstructures on strength and fatigue properties of an Al-Cu-Li thick plate

The inhomogeneity of the microstructure of an Al-Cu-Li thick plate in the thickness direction results in inhomogeneity in the tensile property and fatigue crack propagation (FCP) rate. The grain size gradually increases from the surface layer to the central layer. The contents of low-angle grain boundaries (LAGBs) were characterized by an electron backscattered diffraction (EBSD) technique, and the LAGBs, which act as nucleation sites, induced a greater number of T1 precipitates in the central layer. In the surface layer, the random texture resulted from the greater recrystallization degree due to the high degree of cold deformation during the rolling process. The 1/8 layer contained a rotated cube texture, which is a typical shear texture. A strong β fiber rolling texture was found in the central layer, including S, brass and copper texture components, because the adequate recovery during hot rolling decreased the recrystallization driving force. Both the yield strength (YS) and ultimate tensile strength (UTS) gradually increased from the surface layer to the central layer, i.e., UTS from 479.7 MPa to 546.0 MPa, YS from 455.9 MPa to 514.0 MPa. The inhomogeneity of the tensile properties was primarily caused by the different textures, LAGB content and T1 precipitate density. However, the surface layer had a distinctively lower FCP rate than the central layer. The disparity in the FCP rate between the surface layer and the central layer could be attributed to the roughness and plasticity, which are related to the LAGBs, the T1 precipitates and the grain size.

Effect of Asymmetric Hot Rolling on the Texture Evolution of Fe–3%Si Steel

In Fe–3%Si steel, the hot rolling process affects not only the hot rolling texture but also the primary recrystallization texture. Here, the effect of asymmetric hot rolling was studied by comparing the difference in the texture evolved between asymmetric and symmetric hot rolling. The effect of asymmetric hot rolling on the texture of primary recrystallized Fe–3%Si steel was also studied. The symmetric hot rolling of Fe–3%Si steel produces a rotated cube texture at the center but Goss and copper textures near the surface. Asymmetric hot rolling tends to produce Goss and copper textures even at the center like the texture near the surface. After primary recrystallization, the dominant texture at the center changes from {001} to {111} and the new texture has a higher fraction of the grains which make the low energy boundary with Goss grains than that of symmetric hot rolling.

Texture development during cross rolling of a dual-phase Fe–Cr–Ni alloy: experiments and simulations

Texture development during multi-step cross rolling of a dual-phase Fe–Cr–Ni alloy has been investigated. X-ray diffraction was used to investigate changes in crystallographic texture of both the constituent phases (austenite and ferrite) through changes in orientation distribution function. After deformation, rotated brass (rotated along φ1, i.e. the sample normal direction ND), along with a weak cube texture was observed in austenite, while a strong rotated cube texture was obtained in ferrite. Texture was also simulated for various strains using a co-deformation model by self-consistent visco-plastic (VPSC) formulation. Simulations showed strong rotated brass texture in austenite and a strongly rotated cube, α-fibre (sample rolling direction RD //<1 1 0>) and γ-fibre (ND //<1 1 1>) in ferrite after highest strain (εt = 1.6). VPSC models could not effectively capture the change in crystallographic texture during cross rolling. In ferrite, simulations showed an overestimation of γ-fibre component and an underestimation of rotated cube component. Simulated texture of austenite, on the other hand, showed an overestimation of rotated brass with an absence of cube component. The results are rationalised based on the possible role of shear banding and activation of non-octahedral slip system during cross rolling, both of which are not incorporated in conventional VPSC models.

Microstructural evolution of 2099 Al[sbnd]Li alloy during friction stir welding process

Microstructural evolution of friction stir welded 2099 AlLi alloy was evaluated. Friction stir welding (FSW) resulted in significant grain refinement, dissolution of original phases T1 (Al2CuLi) and δ′ (Al3Li), and precipitation of ultrafine δ′ phases in the nugget zone (NZ). In the heat affected zone (HAZ), heavy precipitation of T1 phases led to a peak hardness of 105HV. A strong rotated Cube texture {013}〈100〉 was obtained in the base metal (BM). After FSW the NZ was characterized by shear texture {111}〈110〉, while Bass texture {110}〈112〉 and S texture {123}〈634〉 were developed in the thermo-mechanically affected zone (TMAZ). Compared with the BM, the dislocation density was decreased in the welding zones, which resulted from recovery and recrystallization.

Microstructure, microtexture and precipitation in the ultrafine-grained surface layer of an Al-Zn-Mg-Cu alloy processed by sliding friction treatment

Precipitate redistribution and texture evolution are usually two concurrent aspects accompanying grain refinement induced by various surface treatment. However, the detailed precipitate redistribution characteristics and process, as well as crystallographic texture in the surface refined grain layer, are still far from full understanding. In this study, we focused on the microstructural and crystallographic features of the sliding friction treatment (SFT) induced surface deformation layer in a 7050 aluminum alloy. With the combination of transmission electron microscopy (TEM) and high angle angular dark field scanning TEM (HAADF-STEM) observations, a surface ultrafine grain (UFG) layer composed of both equiaxed and lamellar ultrafine grains and decorated by high density of coarse grain boundary precipitates (GBPs) were revealed. Further precession electron diffraction (PED) assisted orientation mapping unraveled that high angle grain boundaries rather than low angle grain boundaries are the most favorable nucleation sites for GBPs. The prominent precipitate redistribution can be divided into three successive and interrelated stages, i.e. the mechanically induced precipitate dissolution, solute diffusion and reprecipitation. The quantitative prediction based on pipe diffusion along dislocations and grain boundary diffusion proved the distribution feasibility of GBPs around UFGs. Based on PED and electron backscatter diffraction (EBSD) analyses, the crystallographic texture of the surface UFG layer was identified as a shear texture composed of major rotated cube texture {001} 〈110〉 and minor {111} 〈112〉, while that of the adjoining lamellar coarse grained matrix was pure brass. The SFT induced surface severe shear deformation is responsible for texture evolution.

Cold rolled tungsten (W) plates and foils: Evolution of the microstructure

This paper is the first part of our series on ultrafine-grained (UFG) tungsten produced by cold rolling. The aim of our project is to investigate the correlation between microstructure, mechanical properties and deformation mechanisms in UFG tungsten, a material interesting for future high-temperature applications. For this purpose, a batch of tungsten sheets with different thicknesses has been produced by subsequent cold rolling out of a single sintered compact.The aim of this paper is to characterise the microstructure of the as-received tungsten sheets. Quantitative grain size analysis by EBSD confirms a grain refinement by cold rolling well down into the UFG-regime, reaching 240nm in the S-direction for the 100μm foil. The grain refinement comes with an increase in the number of HAGBs, while LAGBs show no correlation with the degree of deformation introduced by cold rolling. All plates are distinctively textured, the main texture being the {001}〈110〉-orientation (rotated cube texture).Vickers microhardness measurements confirm a steady increase in hardness with advanced rolling up to 687kg/mm2 for the 100μm foil. This indicates that the one-dimensional grain refinement to UFG by cold rolling is sufficient to achieve properties comparable to other UFG tungsten specimens. Therefore, it can be concluded that the batch of samples introduced in this paper will be fit to investigate the evolution of mechanical properties and deformation mechanisms in correlation with the microstructure.