Main Texture Components Research Articles

Multiphysics computational modelling and experimental analysis of friction stir welding of aluminium alloy metal matrix composites (AAMMCs)

Friction stir welding is a modern method for fabricating aluminium alloy metal matrix composites (AAMMCs) that significantly enhance the properties of the parent materials. In this study, Al2O3 particles were incorporated into a 6061-T6 aluminium matrix. Experimental and numerical modeling provided in-situ observations of particle-aluminium matrix mixing in the weld stir zone (SZ). Two different pin profiles, threaded and square, were used to fabricate the AAMMC joints. The threaded pin profile resulted in uniform dispersion and a homogeneous distribution of Al2O3 particles within the aluminium matrix. In contrast, the square pin profile led to defects in the SZ and a non-homogeneous particle distribution. The volume fraction mixing of the AA6061-T6 matrix and Al2O3 at the workpiece/tool interface from top to bottom was analyzed using a level set technique. Experimental results showed effective mixing of Al2O3 particles in the AA6061-T6 matrix with the threaded pin profile, resulting in a defect-free joint, uniform particle distribution, and ultra-fine grain refinement, with grain sizes reduced to 4.19 µm. The main shear texture components observed in the threaded pin joints included B/B̅ and C, along with deformed and recrystallized texture components such as Copper {112} 〈111〉, Brass {110} 〈112〉, Goss {011} 〈100〉, Cube {001} 〈101〉, and P {011} 〈112〉 . Additionally, joints fabricated using threaded pin profiles exhibited significantly higher tensile strength (up to 270 MPa) and microhardness (average of 120 HV0.2) compared to those with square-shaped pin profiles, which showed lower values of 240 MPa and 105 HV0.2, respectively. Thus, AAMMC joints made with threaded pins demonstrate ultra-fine grain refinement, increased high-angle grain boundaries, enhanced recrystallized texture components, and improved mechanical properties, resulting in superior overall joint performance.

The texture evolution near the shear band and corresponding impact on the microvoid nucleation and crack propagation of Ti6242s alloys under high strain rates

This study investigates the texture evolution near the adiabatic shear bands (ASBs) and its impact of on the adiabatic shear failure mechanism, focusing on microvoid nucleation and crack propagation in Ti6242s alloy with an equiaxed α microstructure under high strain rates, using a split Hopkinson pressure bar (SHPB) for the experiments. To achieve this, the initial microstructure was used to enable the texture with the c-axis perpendicular to the loading direction. After compression, the initial texture transformed into two main texture components through different mechanisms. One texture component, aligned parallel to the loading direction, is strongly associated with the {10 1‾ 2} tensile twins, which were widely distributed near the ASBs with their c-axis are 85° to the parent grains in the initial microstructure. The other texture component, with its c-axis perpendicular to the ASB, is formed by the basal slip activation during adiabatic shear deformation. Besides, it should be noted that twinning resulted in the formation of hard grains (with the c-axis of α-grains parallel to the loading direction), increasing the number of hard-soft grain boundaries. A key finding of this paper is the presence of numerous microvoids near the ASB mainly initiated at soft-hard grain boundaries (approximately 65 %), attributed to stress concentration at the boundaries of soft-hard grains, making these boundaries potential nucleation sites for microvoids. Additionally, basal slip bands in the equiaxed α grains provide rapid channels, accelerating the crack propagation rate. This study provides new insights into refining the adiabatic shear failure mechanism under dynamic loading.

The synergistic effect of gradient nanostructure and residual stress induced by expansion deformation on the tension-tension fatigue performance of Ti6Al4V holes

A large number of titanium alloy structural components in aircraft are joined and assembled through holes. The complex service conditions pose high requirements for the fatigue performance of the holes. The study aims to use expansion deformation to induced gradient nanostructures and residual stress enhance the fatigue performance of Ti6Al4V holes. By studying the evolution process of the microstructure in titanium alloys, the formation mechanism of gradient nanostructures has been obtained, and their impact on various stages of fatigue fracture is analyzed. The results showed that the split sleeve cold expansion (CE) process caused severe plastic deformation on the surface of the hole, resulting in a large amount of LAB production and a transformation of the main texture components. Meanwhile, the gradient nanostructures are formed on the hole surface, which include nanocrystalline layer, superfine lath grain layer, lath grain layer and severe deformation layer. During the expansion deformation process, the slip of dislocations leads to the formation of high-density dislocation structures, which evolve into subgrain boundaries and then undergo dynamic recrystallization through subgrain rotation to achieve grain refinement. What's more, the degree of grain refinement, depth of gradient nanostructure, and residual stress increase as the expansion deformation intensifies. The depth of gradient nanostructure is 300 μm, and the maximum residual stress is −419 MPa, when the deformation is 5 %. The combined effect of gradient nanostructures and high residual compressive stress induced by expansion deformation has increased the total fatigue life and crack propagation life of CE-5 specimen by 2.9 and 3.4 times compared to NCE specimen. This work provides an effective method and theoretical analysis for improving the fatigue life of titanium alloy holes.

Cross slip based dynamic recovery during plane strain compression of aluminium and its role in preferential nucleation of the cube-oriented recrystallized grains

Understanding nucleation of the cube-oriented grains during static recrystallization of medium to high stacking fault energy (SFE) FCC metals is both scientifically and industrially important. Dynamic recovery due to weak Hirth junctions is considered as one of the plausible explanations for the nucleation advantage of the cube orientation. However, influence of cross slip based dynamic recovery on the nucleation propensity of the cube orientation has not been studied in detail. For this purpose, we explicitly incorporated stress dependent dynamic recovery of screw dislocations into a dislocation density based crystal plasticity model. The model is utilized for studying influence of cross slip based local dynamic recovery during deformation and recrystallization nucleation of aluminium. We show that dynamic recovery influences local dislocation density difference and disorientation with the neighbouring locations for the main rolling texture components. Next, we analysed nucleation propensity of these texture components using a stochastic nucleation model. Simulation results show that without explicit incorporation of the dynamic recovery of screw dislocations, the Goss orientation shows the highest nucleation propensity. On the other hand, incorporation of the cross slip based dynamic recovery enhances nucleation propensity of the cube component. Therefore, cross slip based dynamic recovery is one of the important mechanisms for nucleation of the cube-oriented recrystallized grains. These results provide new insights into deformation and recrystallization nucleation of medium to high SFE FCC metals.

Effect of nano-SiC particles on grain orientation and hardness of friction stir processed aluminum matrix composite

The present work concentrates on exploiting electron backscatter diffraction (EBSD) and transmission electron microscope (TEM) to investigate the effect of nano-SiC on the microstructure of Al-SiC composites fabricated by friction stir processing (FSP). With the introduction of nano-SiC, the average grain size and the proportion of low angle grain boundaries (LAGBs) decreased to 3.9 μm and 19.3 %, respectively, while the proportion of ∑3 and ∑9 grain boundaries increased slightly. The intensity of the main texture components in Al-SiC composite is reduced compared to FSPed Al. The Schmid factor of the Al-SiC composite decreased to 0.455, and the microhardness increased from 80.0 HV of FSPed Al to 100 HV. During the FSP process, the introduction of nano-SiC not only generates more randomly oriented grains in the composite, but also facilitates the occurrence of dynamic recrystallization.

Microstructural and Textural Evolution of Cold-Drawn Mg-Gd Wires during Annealing Treatment.

In addition to cold drawing, the process of annealing is also essential in the preparation of Mg-4.7 wt%Gd (G4.7) alloy wires. The effect of annealing treatment on the recrystallized microstructure and texture of cold-drawn G4.7 wires was investigated. The results demonstrate that the uniformity and regularity of the recrystallized grains, as well as the annealing texture, impact the follow-up cold drawing performance. When the as-drawn G4.7 wires were annealed at 375 °C, the recrystallized grains were refined, accompanied by uniformity and regularity. Accordingly, the G4.7 wire had a good subsequent drawing deformability, with a maximum accumulative true strain (ATS) of 144%. Additionally, the evolution of the microstructure was consistent with the evolution of the texture. While annealing at a lower temperature (325 °C), the {0002} basal texture of the G4.7 wire was weak, forming the main texture component <101¯0>//DD (the drawing direction). With the increase in temperature, the basal texture was gradually strengthened and the texture component transformed from <101¯0>//DD to a recrystallized texture based on <112¯0>//DD. Even under high-temperature annealing, the G4.7 wire was still affected by the cold-drawn deformation texture and could not fully recover to the as-extruded texture, thus causing a decrease in the subsequent drawing performance.

Effect of deformation temperature on strain localization phenomena in an austenitic Fe-30Mn-6.5Al-0.3C low-density steel

We have investigated the influence of the deformation temperature from 25 °C (RT) to -196 °C on the dislocation structures associated with strain localization phenomena in an austenitic Fe-30Mn-6.5Al-0.3C (wt.%) low-density steel by electron channeling contrast imaging (ECCI), electron backscatter diffraction (EBSD), and bright-field transmitted forescattered electron imaging ((BF) t-FSEI) techniques. The characteristics of the dislocation structures were evaluated on the main texture components, i.e. <111>//tensile axis, <112>//tensile axis, and <001>//tensile axis directions. The inhomogeneous character of the plastic behavior is promoted upon cryogenic deformation due to the formation of dislocation structures associated with strain localization, namely microbands (MBs) and deformation bands (DBs). ECCI analysis of the dislocation structure reveals that the deformation temperature has a strong influence on the thermal-assisted dislocation processes controlling the dislocation configurations and MB formation mechanisms. The MB nucleation mechanism evolves from a cross-slip-assisted mechanism at RT deformation conditions to a slip band-assisted mechanism at cryogenic deformation temperatures. This effect has a profound effect on the grain orientation dependence of the MB structure but not on its crystallographic alignment. On the other hand, cryogenic deformation temperatures (-196 °C) enhance the material's mechanical strength and ductility due to the activation of deformation twinning, which is associated with the reduction of the stacking fault energy. We find that MBs have a small contribution to strain-hardening and ductility due to the small mechanical resistance of these dislocation structures against the advance of deformation twins and dense dislocation layers, and the comparatively small plastic strain accommodated by them, respectively. These findings provide new insights into the microband-induced plasticity (MBIP) effect.

Modeling of dynamic recrystallization texture in hot extruded Mg

Because of the strong effect of texture on the properties of alloys, the evolution of texture during hot extrusion of Mg has been studied through experiments and simulations. For a better understanding of the texture evolution at high processing temperatures, the model based on viscoplastic formulation was extended to a cellular automaton procedure to consider the recrystallization mechanisms. Texture evolution was simulated for the basal, prismatic and pyramidal 2nd order slip systems. Twinning was not considered because no twins were observed in the microstructural investigation. In the experimental investigations, the samples were extruded to a strain of ε = 2.7 at different temperatures, namely 180 °C, 280 °C, and 380 °C. The microstructure, texture, and hardness were evaluated by optical and electron microscopy using EBSD, X-ray diffraction, and Vickers tests, respectively. The main textural components were identified for each deformation temperature. Based on the simulations, a mechanism for the formation of a specific component was proposed. It was found that the change in the main texture component depends not only on the critical resolved shear stress for a specific slip system but also on the recrystallization parameters. The vpsc model has been shown to predict only the deformation texture components because the temperature is accounted for in accordance with the critical resolved shear stress and rate sensitivity. These two parameters affect the slip system activity. The new model using the cellular automaton procedure, which covers recrystallization processes, produces textures that fall in line with the experimental results.

Phase Transformation Crystallography in Pipeline HSLA Steel after TMCP

Thermo-mechanical controlled processing (TMCP) is employed to obtain the required level of mechanical properties of contemporary high-strength low-alloy (HSLA) steel plates utilized for gas and oil pipeline production. The strength, deformation behavior and resistance to the formation and propagation of running fractures of the pipeline steel are mainly determined by its microstructure and crystallographic texture. These are formed as a result of austenite deformation and consequent γ→α-transformation. This present study analyses the crystallographic regularities of the structural and textural state formation in a steel plate that has been industrially produced by means of TMCP. The values of the mechanical properties that have been measured in different directions demonstrate the significance of the crystallographic texture in the deformation and failure of steel products. An electron backscatter diffraction (EBSD) method and crystallographic analysis were utilized to establish the connection between the main texture components of the deformed austenite and α-phase orientations. This paper demonstrates that the crystallographic texture that is formed due to a multipath γ→α-transformation results from the α-phase nucleation on the special boundaries between grains with γ-phase orientations. The analysis of the spectra of the α-γ-interface boundary angle deviations from the Kurdjumov–Sachs (K–S), Nishiyama–Wassermann (N–W), and Greninger–Troiano (G–T) orientation relationships (ORs) allows to suggest that the observed austenite particles represent a secondary austenite (not retained) that precipitates at intercrystalline α-phase boundaries and correspond to the ORs with regard to only one adjacent crystallite.

The Differences in Microstructure, Microtexture, and Tensile Anisotropy of Ti80 Heavy Plate Across the Thickness

Herein, the differences in microstructure, microtexture, and tensile behavior of the Ti80 heavy plate across the thickness are investigated. The Ti80 heavy plate consists of equiaxed α and transformed β grains with high degrees of recrystallization microstructures. Significant differences are observed in the main texture components between the central and surface zones. The inhomogeneous distribution of hot compression and shear leads to different deformation textures during processing. Due to temperature distribution, the combination of the variant selection mechanism and α–β phase interaction is responsible for the evolution of surface texture, while only the former plays a major role in the center. Final fracture areas of tensile samples show ductile fracture characteristics. The anisotropy behaviors in planar tensile of the Ti80 heavy plate at room temperature are evaluated. They are related to the difficulty of activating prismatic slip and basal slip , which are determined by the crystallographic texture of the material. This work helps to explore reasonable thermomechanical processing parameters and establish rolling schedules to weaken the mechanical heterogeneity across the thickness of near‐α‐titanium alloy heavy plates.

Regularities of structure and texture development in austenitic steel during cold rolling and heat treatment

The paper studies the regularities of the structure and texture formation in austenitic steel AISI 304 under cold rolling and subsequent heat treatment. Regularities of structure and texture formation depending on the rolling type and deformation degree were established. The ratios of main texture components, the volume fractions and the distortion of the martensite's crystalline lattice were analyzed. It is shown that mechanisms of the austenite martensite phase transformation in the course of cold rolling may change depending on various deformation schemes, as well as mechanisms of the reverse phase transformation variate under subsequent annealing. Herewith depending on the rolling type and deformation degree, the crystallographic texture formation of the nucleating austenite under the heat treatment can have single component or multi-component character and follows different orientation relations. The more scattered martensite texture after deformation results in the formation of fine-dispersed austenite, which hardens the material keeping a sufficient level of plasticity. The work was carried out with the financial support of&nbsp;the Ministry of Science and Higher Education of Russian&nbsp;Federation (Agreement No. 075-15-2021-1352).

Role of dynamic recrystallization and grain growth on the formation of abnormal basal texture in a high-alloyed Mg-Al-Zn extruded alloy

A commercial Mg-8.1Al-0.58Zn-0.27Mn alloy (mass%, AZ80) was extruded using different temperature and extrusion ratio. The microstructural development was thoroughly investigated by electron backscatter diffraction. A typical basal texture with the vertical alignment of the (0001) poles to the extrusion direction became main texture component regardless of the extrusion conditions. Notably, dynamically recrystallized grains, which had the parallel alignment of the (0001) poles to the extrusion direction, were formed at the initial stage of extrusion. However, such abnormally textured grains were consumed by basal-textured grains when the extrusion was performed at a relatively low temperature or using a high extrusion ratio of 50. In contrast, apparent intensity corresponding to the abnormal texture component was preserved during the extrusion at 400 °C using a relatively low extrusion ratio of 10. The low extrusion ratio facilitated the growth of the abnormally textured grains, which maintained a certain amount of the texture component having the parallel alignment of the (0001) poles to the extrusion direction.

Unveiling the rolling texture variations of α-Mg phases in a dual-phase Mg-Li alloy

LZ91 Mg-Li alloy plates with three types of initial texture were rolled by 70% reduction at both room temperature and 200 °C to explore the rolling texture formation of α-Mg phase. The results showed that the rolling texture is largely affected by the initial texture. All the samples exhibited two main texture components as RD-split double peaks texture and TD-split double peaks texture after large strain rolling. The intensity of the two texture components was strongly influenced by the initial orientation and rolling temperature. Extension twinning altered the large-split non-basal orientation to a near basal one at low rolling strain. The basal orientation induced by twinning is unstable, which finally transmitted to the RD-split texture. The strong TD-split texture formed due to slip-induced orientation transition from its initial orientation. The competition between prismatic 〈a〉 and basal slip determined the intensity and tilt angle of the TD-split texture. By increasing the rolling temperature, the TD-split texture component was enhanced in all three samples. Limitation of extension twinning behavior and the promotion of prismatic slip at elevated temperature are the main reasons for the difference in hot and cold rolling texture.

Microstructure and texture evolution of pure niobium in cold-drawn Mg+B/Nb/Cu wires

In this study, Mg+B wires were prepared by powder in tube method using Nb and Cu tubes as barrier and sheath, respectively, followed by cold drawing. Microstructural, textural, and mechanical properties of the Nb barrier at different drawing strains (ε d) were investigated. The results showed that the Nb barrier demonstrated a saturation hardness of 159.4 HV. The microstructure of the Nb barrier became elongated along the drawing direction increasing ε d. Sub-grains existing inside the deformed grains rotated from low-angle grain boundaries to high-angle grain boundaries and developed into new grains. The main textural components of the Nb barrier were {111} γ-fiber and {hkl}〈110 〉 α-fiber. Recrystallized grains exhibited a low maximum orientation distribution function intensity, weak {100}〈110 〉 α-fibers, and strong {111}〈110 〉 γ-fibers as compared to those of the deformed grains. The relationship between the microstructure evolution and mechanical properties of the Nb barrier and the changes in the cross-sectional area fractions of the materials constituting the Mg+B composite wire are discussed. The current study provides details about the misorientation profile inside deformed grains and continuous dynamic recrystallization mechanism of the cold-drawn Nb barrier.

Microstructural study of microbands in a Fe-30Mn-6.5Al-0.3C low-density steel deformed at cryogenic temperature by combined electron channeling contrast imaging and electron backscatter diffraction

The microstructural characteristics of the microband (MB) structure in an austenitic Fe-30Mn-6.5Al-0.3C (wt.%) low-density steel tensile deformed at -196 °C were investigated by combined electron channeling contrast imaging and electron backscatter diffraction. The nucleation mechanisms and grain-orientation dependence of the most relevant microstructural features of the MB structure, namely, morphology, internal dislocation configuration, and alignment were quantitatively analyzed on the main texture components, i.e. <111>//tensile axis and <001>//tensile axis directions. The present study shows several unrevealed microstructural characteristics of MBs in austenitic Fe-Mn-Al-C low-density steels deformed at cryogenic temperatures. The analysis of the interplay between the activated slip systems and the microstructural characteristics of the MB structure provides further insight into the nucleation mechanisms and the boundary alignment. Several in-grain and grain boundary-assisted MB nucleation mechanisms were identified. At low strain levels (ε = 0.3), MB formation is controlled by planar slip localization phenomena acting on closely spaced slip bands. The MB structure is localized in the grain interiors of areas containing intense plastic localization. At high strain levels (ε = 0.6), the MB structure only develops in grains that are not favorable oriented for deformation twinning, i.e. grains oriented close to <001>//TA directions. At this deformation stage, the deformation behavior becomes highly inhomogeneous due to the activation of an in-grain macroscopic localization phenomenon associated with moderated lattice rotations (∼ 3–5°). It leads to the formation of a complex deformation structure formed by macroscopic deformation bands containing arrays of crystallographic MBs. The analysis of the MB alignment reveals several interesting features such as the formation of non-crystallographic MBs aligned along (3 -1 5) and (3 5 -1) planes. Their formation can be explained in terms of the lattice rotations accommodated by the active slip systems predicted by Winther's model.

Investigation of Through-Thickness Residual Stress, Microstructure and Texture in Radial Forged High-Strength Alloy Steel Tubes

Gradient variations of through-thickness residual stress, microstructure and texture greatly affect the performance of cold radial forged tubes. In this work, the through-thickness distribution of residual stress was measured based on the Debye ring. The microstructure was characterized with the electron backscattering diffraction technique. The texture was measured by the X-ray diffractometer. The influence of microstructure and texture on the strength and anisotropy of forged tubes with different thickness reductions was analyzed. The results show that the residual stress varies gradually from compressive to tensile from the outer to inner surface. The microhardness of the outer surface is lower than the inner. The dislocation density and low-angle grain boundary fraction are the smallest in the one-third thickness. The dislocation density and low-angle grain boundary fraction increase gradually from the one-third thickness to the inner surface. The main texture components of the forged tube include {111}&lt;110&gt;, {001}&lt;110&gt; and {114}&lt;110&gt;. Texture {111}&lt;110&gt; deflects gradually toward {114}&lt;110&gt;, {112}&lt;110&gt; and {110}&lt;110&gt; from the external tube to the internal tube. The gradient variation of strength mainly resulted from the difference of the dislocation density. The difference of strength along the radial direction is reduced with a larger thickness reduction. This work has important significance for improving the performance of high-strength alloy steel tubes processed by cold radial forging.

Effect of microstructure and texture on the mechanical properties in high strength pipeline bend

This paper focuses on the effect of microstructure and micro-texture on the mechanical properties in high strength pipeline bend. The transmission electron microscopy (TEM), and electron backscatter diffraction (EBSD) were performed on the microstructure and texture observation. Tensile tests and Charpy V-notch impact tests were used to measure the strength and impact toughness, respectively. After hot induction bending, the microstructure of both the inner arc side and the neutral axis position has some polygonal ferrite (PF) grains. High-density dislocations, M/A constituents in the bainite laths, and high frequency of high Taylor factor in the outer arc side result in the toughness lower than the other specimens. In addition, dynamic recovery and partial recrystallization occurred during hot induction bending, the recrystallized grains are small and scattered distribution in the inner arc side and the outer arc side. The results indicated that the mechanical properties of the outer arc side have anisotropy along with the longitudinal and transversal directions. Micro-texture results obtained by EBSD measurement show that the main texture components in the experimental specimens are Cube, Goss, Brass, Copper, R-cube, and {331} <1–10> possibly because of the same mother pipe. However, the Brass and {112} <110>component might be the major factor of the anisotropy for the experimental bend.

Моделирование кристаллографической текстуры феррит / мартенситной стали при прокатке: уровень и анизотропия прочностных свойств

This paper presents the results of studies of the level and anisotropy of strength properties in ferritic / martensitic steel during warm rolling based on the data on crystallographic texture. The features of texture formation processes in the initial and UFG samples subjected to flat rolling are analyzed by the method of texture analysis and computer modeling. In particular, the analysis of the orientation distribution function (ODF) made it possible to establish the change in the main preferential orientations (Brass, Goss, Copper, Cube, TC, Y, Z and Rotated Cube) depending on the degree of reduction. It is shown that in flat rolling, a stable rolling texture is formed only after 70 % reduction, at which H {001}<011>, Goss {001}<110>, Cube {100}<001> and TC {255}<511> orientations become the main ones. At high degrees of flat rolling, the sharpness of the above textural maxima increases, which is accompanied by the activation of a smaller number of slip systems, and the misorientations between adjacent grains become predominantly high-angle ones. Within the framework of modeling of crystallographic textures, deformation mechanisms were established, two-dimensional projections of yield contours, Young's module and Lankford coefficients (r-value) were constructed. In particular, the results of computer simulation of the yield contours of steel after tempering the coarse-crystalline and UFG states showed that at low degrees of flat rolling reduction, an increased level of anisotropy of strength properties is associated with the residual crystallographic texture in the workpiece, and an increase in the degree of flat rolling leads to alignment of the strength anisotropy in sheets. It was found that the quantitative ratio of the main textural components of the type H {001}<011>, Goss {001}<110>, Cube {100}<001> and TC {255}<511> during rolling determine the anisotropy of the strength properties of steel.

Effect of heat input on microstructure and corrosion resistance in heat affected zone of 304 stainless steel joint by laser welding

Laser welding of 5 mm thick 304 austenitic stainless steels without grooves was carried out, and the effect of heat input and cooling time on grain boundary character distribution (GBCD), texture evolution, corrosion behavior in the heat affected zone was investigated in detail. The experimental results revealed that the fractions of low Σ coincidence site lattice (CSL) grain boundary increase and random high angle boundaries decrease by prolonging the cooling time and heat input. In addition, the dynamic recrystallization of the heat affected zone (HAZ) is influenced significantly by heat input, which resulted in the evolution of the textures. The main texture components were concentrated around {210}< 112 > and {111}< 112 > when subjected to large heat input. Moreover, the corrosion resistance was improved by increasing the cooling time, which was tested by the potentiodynamic polarization test.

Effect of annealing temperature on anisotropy of mechanical properties in powder metallurgy FeCoCrNiN0.07 high-entropy alloy sheets

In this study mechanical properties and texture of powder metallurgy FeCoCrNiN0.07 HEA sheets were studied at cold-rolled and different annealed conditions. The results show that the sheets at the cold-rolled (CR) condition and annealed state at 500 °C (anneal-500) exhibit obvious anisotropy of mechanical properties and the strength along the rolling direction is lower than that in the 90° direction. This mechanical anisotropy reduces significantly in the sheet after annealing at 750 °C (anneal-750). The main texture components are F {111} <112>, Goss {110} <001>, G/B {110} <115> and E {111} <110> texture for the CR condition, and F {111} <112>, Goss {110} <001>, Brass {110} <112> and E {111} <110> texture for the anneal-500 condition, respectively. The mechanical property anisotropy of the FeCoCrNiN0.07 sheet could be well explained by the equivalent Schmid factors (ηsD) which are calculated by weighting the maximum Schmid factors (ηsmax) for different texture components along different loading directions using their volume fractions. The equivalent Schmid factors of CR and anneal-500 sheets in the 0° (rolling direction), 45° (an angle of 45° to the rolling direction) and 90° (perpendicular to the rolling direction) directions gradually decreased in order, which fits well with that the strengths in the 0°, 45° and 90° directions gradually increased in sequence. The anneal-750 sheet has undergone significant recrystallization and the anisotropy of mechanical properties is greatly reduced consequently.