Deformation Texture Evolution Research Articles

Dual-phase polycrystalline crystal plasticity model revealing the relationship between microstructural characteristics and mechanical properties in additively manufactured maraging steel

To elucidate the relationship between microstructural characteristics and mechanical properties in additively manufactured (AM) maraging steel, this study introduces a computational approach that addresses two fundamental challenges. Firstly, it addresses the creation of representative volume elements (RVEs) that mimic the observed microstructural complexities, such as meltpool boundaries, prior austenite grains, packets and blocks of lath martensite. This is accomplished through the application of Potts Monte-Carlo methods and grain segmentation techniques in accordance with the Kurdjumov–Sachs orientation relationship. Secondly, this study develops a comprehensive crystal plasticity (CP) model encompassing both bcc and fcc plasticity. Inspired by atomistic and discrete dislocation dynamics studies, the proposed CP model incorporates characteristics intrinsic to bcc plasticity, including non-Schmid effects, dislocation and precipitate strengthening, and Hall–Petch type strengthening of elongated martensitic blocks. Utilizing the created RVEs and the proposed CP framework, finite element simulations are conducted based on an update-Lagrangian formulation. The purpose of this study is to investigate the deformation behavior, texture evolution, tension–compression asymmetry, and evolution in dislocation density in RVEs representative of as-built and heat-treated samples of maraging steel. This computational approach and its findings deepen our understanding of the intricate interplay between microstructural characteristics and mechanical properties in maraging steel and also provide valuable guidelines for refining its additive manufacturing and heat treatment processes.

An investigation to microstructural and texture evolution during the cold rolling of Al0.3CoCrFeNi high entropy alloy

In the present study, Al0.3CoCrFeNi high entropy alloy (HEA) was subjected to thickness reductions through cold rolling process in order to thoroughly investigate the evolution of microstructure and deformation texture. Important aspects of deformed microstructures such as the formation of twinning bundles and shear bands in the specimens were monitored. The evolution of texture during the cold rolling process was measured by X-Ray Diffraction (XRD) and Electron Back Scatter Diffraction (EBSD) technique which revealed the formation of Copper type texture at the initial stages of rolling due to slip deformation mechanism. Originated from twinning and followed by shear banding, the texture was subsequently developed toward predominantly Brass type. Microstructural features and texture evolution behavior of the investigated single phase FCC alloy was attributed to its low SFE level. Visco Plastic Self Consistent (VPSC) technique was coupled in the research to simulate the material behavior and to examine the contribution of slip and twinning systems. Benefiting VPSC justifications, the texture transition from Copper type to Brass type was related to lower CRSS value of slip in comparison to twinning at the small strains which was then grows faster at the later stages of rolling facilitating the onset of twinning and providing the texture transition basement.

Microstructure and texture evolution in AZX311 Mg alloy during in-plane shear deformation

The current study examined the deformation mechanisms, microstructure, and texture evolution in AZX311 Mg alloy sheets subjected to in-plane shear (IPS) deformation. Different levels of shear strains, with values 0.05, 0.10, and 0.15, were applied along the rolling direction (RD) using a specialized in-plane shear testing jig. The strain measurement for the applied shear deformation was conducted utilizing the digital image correlation (DIC) technique. The strain distribution was found to be nearly homogeneous over sufficiently large areas, thereby allowing the microstructural measurements to yield relevant statistical data. A thorough microstructural examination across the thickness using electron back-scattered diffraction (EBSD) revealed that the application of IPS strain led to the formation of a significant number of tensile twins (TTWs) in the sheet. This was evidenced by the emergence of two satellite peaks at the periphery of the pole figures. As the shear strain increased, the proportion of TTWs in the material also increased, encompassing the entire parent grain and leading to the formation of what has been termed as “all-twinned microstructure”. The microstructural and texture investigation after IPS deformation revealed that TTWs were the dominant deformation mechanism that defined the microstructure and texture under IPS deformation, while dislocation slip activity was dominated by prismatic slip, as evidenced by the resolved shear stress analysis in this study. Consequently, this research highlights the effect of IPS deformation on the microstructure and texture evolution throughout the thickness of an Mg alloy sheet and elucidates the underlying mechanisms.

Texture and Twinning Evolution of Cold-Rolled Industrial Pure Zirconium

Industrial pure zirconium plays an essential role as a structural material in the nuclear energy sector. Understanding the deformation mechanisms is crucial for effectively managing the plasticity and texture evolution of industrial pure zirconium. In the present study, the texture and microstructure evolution of industrial pure zirconium during the cold-rolling process have been characterized by XRD, EBSD, and TEM. The influences of various twins on texture evolution have also been simulated by the reaction stress model. The effects of slip and twinning on the deformation behavior and texture evolution have been discussed based on crystallographic and experimental considerations. Cold rolling yields a typical bimodal texture, resulting in the preferential <21-1-0>//RD orientation. The activation of the deformation mechanisms during cold rolling follows the sequential trend of slip, twinning, local slip. Experimental characterization and reaction stress simulation illustrate that T1 twins dominate in the early stage, whereas C2 twins develop at the later stage of the cold-rolling process. Twinning, especially the T1 twin, contributes to the formation of the {0001}<101-0> orientation.

Temperature dependent deformation behavior and texture evolution in AA6082 aluminum alloy: An integrated experimental and crystal plasticity simulation approach

This research provides a comprehensive analysis of the texture and temperature dependent deformation behavior of the aluminum alloy AA6082. The study is performed using a combination of experimental deformation tests and computational simulations using a crystal plasticity (CP) framework. The primary objective is to identify the critical influence of temperature on local stress states and dislocation density within the material during tensile tests. From an experimental perspective, the study employs ex-situ deformation tests and subsequent electron backscatter diffraction (EBSD) data in combination with energy dispersive x-ray spectrometer (EDS) analysis at 200 °C and 400 °C. The experimental EBSD data are adopted, preprocessed and converted into a geometry file for the numerical simulations. On the computational front, a dislocation density-based material model is adopted for CP simulations. The physical and fitting parameters of the model are calculated, adopted from the literature, or calibrated by comparing the global simulation results with experimental stress-strain observations under uniaxial tensile load at room temperature, 200 °C and 400 °C. Empirical functions for solid solution strengthening, dislocation density, fitting parameters controlling mean free path and dislocation annihilation have been derived that can be used to quickly interpolate them for any intermediate temperature. These functions combined with other model parameters can now be used for temperature-dependent CP modeling of AA6082. The isothermal grain-scale simulation and ex-situ experimental results confirmed a noteworthy texture transformation at higher temperatures, characterized by a reduction in the primary Cube orientation and its transition into a Copper orientation due to the stretching process. The correlation between the experimental results and the simulations on macro- and micro-scales is reasonable, indicating the accuracy and effectiveness of the CP approach in predicting the temperature dependent deformation behavior and texture evolution in aluminum alloys.

The origin of {113}<361> grains and their impact on secondary recrystallization in producing ultra-thin grain-oriented electrical steel

Abstract Ultra-thin grain-oriented electrical steel with a thickness of 80 µm is produced by one-step-rolling with industrial grain-oriented electrical steel. The research employs electron back-scattering texture analysis technique to investigate the evolution of deformation and recrystallization textures in this specific steel. Emphasis is placed on examining the origin of {113}<361> grains and their consequential impact on secondary recrystallization. It is revealed that primary, secondary, and tertiary recrystallization phases are integral during the annealing process. The origin of surface {113}<361> grains were result of initial deviated Goss grains with specific shear deformation behavior in cold rolled ultra-thin strips. Additionally, the influence of these grains on texture evolution is predominantly evident during secondary recrystallization. These grains potentially undergo abnormal growth in secondary recrystallization, exploiting high-energy grain boundaries among Goss grains. This phenomenon consequently leads to the diminution of the sharp Goss texture formed during primary recrystallization. Given the magnetic properties and predominant applications of ultra-thin grain-oriented electrical steel in medium-frequency fields, it is recommended to prepare ultra-thin grain-oriented steel during primary recrystallization phase.

Deformation substructure and texture evolution of (VCoNi)99.9C0.1 medium-entropy alloy under different rolling reductions

The deformation substructures and texture characteristics of (VCoNi)99.9C0.1 medium-entropy alloy (MEA) upon the different rolling reductions were systematically investigated in this work. The rolling deformation caused the deviation of annealing twin orientation and thus led to the gradually reduced annealing twin variants. The dislocation induced-orientation analysis was carried out within the deformed grains, confirming the presence of three kinds of orientation spreads (type 1, type 2 and type 3). The dominant orientation spreads of type 1, type 2 and type 3 were emerged in a sequential order of low, medium and heavy strains, respectively. As strains progressed, the intensities of 111<12̅1> R1 and {111}<011̅> R2 components were significantly weakened, while {112}<111̅> Copper and {123}<634̅> S components were consistently persisted with the strengthening orientations. For the heavily deformed sample, the strong {110}<001> Goss and {110}<11̅2>Brass components were revealed and the maximum intensity was obtained at a location between Goss and Brass components, which were ascribed to the chemical short-range order-assisted planar slip. It was worth noting that the carbide particles show the weak effect on the texture components and intensity distribution. As increasing rolling reductions, rolling deformation led to the significant improvement of strength, due to the work hardening.

Deformation Behavior and Texture Evolution of Ferrite and Austenite Phases in Lean Duplex Stainless Steel

To avoid cracks during hot rolling, a short process of direct cold rolling following solution treatment of the casting billet for preparing lean duplex stainless steel plates is proposed. The effect of cold rolling reduction on the microstructure, texture, and mechanical properties of UNS S32101 is investigated. The results show that dislocation slip is the main character in ferrite, which leads to dislocation tangles, dislocation cells, high‐density dislocation walls, and deformed microbands. However, twinning and strain‐induced martensite transformation (SIMT) occur in austenite, and the SIMT mechanism of austenite follows the classical model γ → ε → α′ and γ → α′, with the orientation relationship of Kurdjumov–Sachs ( and ) and Nishyama–Wassermann (N–W) ( and ). Meanwhile, at 50%, there is a transition from Cu texture to Brass texture in the austenite phase. At 12.5%, the yield strength is 344 MPa higher than that of the traditional hot rolling process, and the elongation remains about 35%. With the increasing cold rolling reduction, the elongation decreases while the strength rises significantly. Strengthening dislocations, fine‐tuning grains, and SIMT are the primary contributors to the improvement in strength.

Strain rate and anisotropic effects on incipient plastic deformation of Zn–Cu–Ti alloy sheets

Zinc alloys shows strong strain rate dependent and anisotropic mechanical behaviours, the mechanistic origin of which is however not fully understood. In this work, a combination of the experiments and crystal plasticity finite element simulations were used to gain an insight into the relation between deformation mechanisms, tensile deformation behaviour and texture evolution, especially for the incipient plastic deformation stage. To this end, specimens were cut from Zn–Cu–Ti alloy sheets at various orientations with respect to the rolling direction, and uniaxial tensile tests were conducted at different strain rates ranging from 10−3 to 5 × 10−2 s−1. The microstructure evolution with the deformation was examined by the electron backscatter diffraction technique. Crystal plasticity model was calibrated considering the effect of strain rate on the flow stress, and finite element simulations were carried out based on a representative volume element of the polycrystal zinc alloy. It is found out that the flow stress increases significantly, as the loading direction approaches the transverse direction, which results in a lower relative activity of basal slip and higher relative activity of non-basal ones. This, in turn, reduces the rotation of the c-axis of the crystallites towards ND during tensile tests. On the other hand, a positive strain rate sensitivity is found in the zinc alloy. Meanwhile, increasing strain rate leads to an obvious decrease in the activity of the pyramidal π-II slip systems, accompanied by more activated twinning systems. The lower activity of the pyramidal π-II slip at a higher strain rate probably hinders the development of CDRX and grain fragmentation at large strain levels.

Mechanical behaviour and microstructural evolution of Ti–6Al–1Mo–1V–2Zr–2Cr–1Fe alloy subjected to hot compression deformation

A new titanium alloy with chemical composition of Ti–6Al–1Mo–1V–2Zr–2Cr–1Fe (wt.%) is designed and produced. The hot deformation behavior, microstructural evolution and texture evolution of the alloy after solution treatment are investigated in this paper. Firstly, the constitutive equation of solution-treated Ti–6Al–1Mo–1V–2Zr–2Cr–1Fe alloy with the consideration of strain compensation is obtained based on compressive test at the temperatures of 950–1100 °C and the strain rates of 0.01–10 s−1, which can be used to describe the flow behaviour at elevated temperatures. According to the corresponding constitutive equation, the flow stress of solution-treated alloy is accurately predicted, which is further verified by the experimental data. Furthermore, discontinuous dynamic recrystallization (DDRX) and continuous dynamic recrystallization (CDRX) are observed in the microstructures of the deformed alloys, where deformation temperature and strain rate have a significant effect on DDRX and CDRX processes of solution-treated Ti–6Al–1Mo–1V–2Zr–2Cr–1Fe alloy. Moreover, plastic deformation and dynamic recrystallization have a comprehensive influence on the texture evolution of solution-treated Ti–6Al–1Mo–1V–2Zr–2Cr–1Fe alloy. ηbcc-fiber textures of {100}<001> and {110}<001>, εbcc-fiber texture of {112}<111> and ξbcc-fiber texture of {110}<112> are the main texture compositions of the deformed samples, where all of the deformed samples exhibit a strong {100}<001> texture.

Field fluctuations viscoplastic self-consistent crystal plasticity: Applications to predicting texture evolution during deformation and recrystallization of cubic polycrystalline metals

Recent advances pertaining to modeling of grain fragmentation during deformation and recrystallization of polycrystalline metals using viscoplastic self-consistent (VPSC) polycrystal plasticity are combined into a field fluctuations VPSC (FF-VPSC) model. The FF-VPSC model is a higher-order formulation calculating the second moments of lattice rotation rates based on the second moments of stress fields inside grains and resulting intragranular misorientation distributions. The misorientation distributions are used to define a grain fragmentation sub-model for improving predictions of deformation texture evolution and to formulate kinetics sub-models for nucleation as well as to influence the stored energy governing grain growth for the predictions of recrystallization texture evolution. Formation of a copper-like texture in moderately high stacking fault energy (SFE) Cu and a brass-like texture in low SFE brass during rolling to very large strains are successfully predicted using the model. Remarkably, the model also predicts recrystallization textures from the deformation textures of the two metals after adjusting tradeoffs between transition-bands and grain boundary nucleation mechanisms. Additionally, rolling and recrystallization of an interstitial-free steel, tension and recrystallization of AA5182-O, and recrystallization of an additively manufacturing cobalt-based alloy MarM-509 are simulated to predict texture evolution. Through these case studies involving multiple alloys and thermo-mechanical processes we show that, in addition to being predictive with good accuracy, the key advantage of the model lies in its versatility. The FF-VPSC model, simulation results, and insights from the results are presented and discussed in this paper.

Effect of deformation mode on double-peak texture evolution in pre-twinning Mg-3Al-1Zn alloy during high-speed impacting loading

An investigation of the quantitative effect of the deformation process on the deformation mode, texture evolution, and their internal relationship could help control the mechanical properties of targeted materials. In this study, the deformation mechanism and texture evolution of pre-twinning AZ31 magnesium alloy under medium temperature with high-speed impact loading are investigated through electron backscattered diffraction and the coupled simulation of the finite element method and viscoplastic self-consistent models. Basal and < c + a > pyramidal slips are the dominant accommodation modes. The activation of nonbasal slip is promoted, and the number of twins increase with an increase in the impact pressure, leading to a decrease in the relative activity of the basal slip. Based on typical grain rotation statistics, the effects of basal slip, pyramidal <c + a> slip, and extension twins on grain rotation are studied. With an increase in the pressure, the relative activity difference between the basal slip and pyramidal <c + a> glide decreases, which is beneficial for the formation of a double-peak basal texture and the enhancement of the intensity of the double-peak texture. The twin density affects the split angle between the double peaks.

Enhanced deformability of WE43 magnesium alloy by activation of non-basal slip and twinning deformation modes in the equal channel angular pressing at room temperature

Activation of the prismatic and pyramidal slip systems, along with the twinning as the secondary deformation mechanism, assists in the accommodation of a larger plastic strain during the deformation of magnesium alloys. In this paper, deformation mode activity and texture evolution of the WE43 magnesium alloy were investigated during core-sheath equal channel angular pressing (ECAP) at room temperature. Texture studies and transmission electron microscopy inspections suggest that the mechanisms behind the ECAP at room temperature assisted by back pressure were activation of (101¯0) prismatic slip (as the primary mechanism), as well as extension and contraction twinning.

Microstructure-crystallographic texture and substructure evolution in unpeened and laser shock peened HSLA steel upon ratcheting deformation

ABSTRACT Uniaxial ratcheting behaviours associated with microstructural development of unpeened and laser shock peened ASTM A 588 Grade D High Strength Low Alloy (HSLA) steel were studied in this investigation. The mechanism of plastic deformation and crystallographic texture evolution during ratcheting was also studied. For this, the primary experimental works involved were stress-controlled ratcheting fatigue tests (on unpeened/laser-peened specimens) at room temperature. Followed by this, microstructure and texture evolution on the surfaces and/or cross sections of the deformed specimens, using electron back scattered diffraction (EBSD) were studied in detail. Additionally, the substructural evolution of some selected samples was also studied using transmission electron microscopy (TEM). The results indicated that the average grain size of all the unpeened ratcheted specimens was marginally reduced after fatigue tests. The laser-peened specimen, however, showed a marginal increase in average grain size after ratcheting. Continuous dynamic recovery and recrystallisation (CDRR) during ratcheting was thought to be the cause of the observed reduction in average grain size in unpeened specimens, whereas continuous dynamic recrystallisation (CDRX) was believed to be the controlling factor for marginal accretion of grain size in laser-peened specimens. The plastic deformation of investigated steel was qualitatively explained by the observed dislocation patterns and their evolution.

Microstructural Influence on Fracture Toughness of IF Steel and DP Steel

Interstitial free steels (IF) and Dual-phase (DP) steels are widely used in the automotive industry, their specific application is driven by requirements to optimize the strength-to-weight ratio. Utilizing the full capacity of their plasticity and strain hardenability requires an assessment of edge fracture susceptibility and flangeability. In this work, the ability of the mentioned steels to spreading of deformation along initiated cracks is evaluated by structural and fractographic analyzes. Microstructural restrictions of plasticity are correlated with fracture toughness results, adopting the essential work of fracture (EWF) methodology. Crystallographic analyzes (EBSD) are focused on the role of anisotropy and the deformation texture evolution, affecting the development of plasticity and thus the energy consumption to the fracture.

The hot deformation behavior, microstructure and texture evolution of homogenized Mg–9Li–1Zn alloy

In this study, the hot deformation behavior, microstructure and texture evolution of Mg–9Li–1Zn (LZ91) alloy were investigated systematically, and the best Arrhenius hot deformation constitutive equation model and processing map of the LZ91 alloy were developed. Hot compression tests were performed at deformation temperatures and strain rates ranging from 175 °C to 275 °C and 0.001 s−1 to 1 s−1, respectively. The results showed that Arrhenius constitutive equation can predict accurately the hot deformation behavior of LZ91 alloy. The instability areas for this alloy were concentrated in the range of 175 °C–220 °C, 0.01 s−1–0.1 s−1 and 225 °C–260 °C, 0.001 s−1–0.002 s−1 and 0.02 s−1–1 s−1. The observation of microstructure revealed that the alloy is deformed by the cooperation of the basal slip system and the pyramidal conical slip system. In addition, the hardness which increases in a gradient from the center to the edges is the result of the combined effect of grain refinement and texture.

The role of molybdenum on evolution of deformation texture in the cold rolled Fe30Mn5Al1C-xMo lightweight austenitic steels

The effect of molybdenum addition on the evolution of deformation texture during cold rolling is studied in Fe30Mn5Al1C-xMo (x = 0−3 wt%) light weight austenitic steels using EBSD. All the alloys have random texture prior to cold-rolling. After cold rolling, molybdenum promoted the formation of Brass-type texture. This texture can be attributed to dislocation based active deformation mechanisms because no deformation twins were found in the microstructure. The intensity of the major texture components: Brass and S increased up to 2 wt% Mo and then decreased. The increase in the molybdenum content did not affect mechanical properties significantly.

Mechanism of Plastic Deformation of As-Extruded AZ31 Mg Alloy during Uniaxial Compression

The deformation mechanism and texture evolution of AZ31 Mg alloy compressed in three different directions at room temperature were studied, and the relationship between the two was compared through experiments and viscoplastic self-consistent (VPSC) modeling. Setting up only one specific deformation mode was the predominant mechanism by changing the CRSS ratio for the different deformation modes. The following conclusions were drawn: (1) It was demonstrated that basal slip causes a slow and continuous deflection of the grain toward the transverse direction (TD). When the sample is compressed in the extruded direction (ED), prismatic slip leads to grains being deflected toward the ED in the initial stages of compression, and when the sample is compressed 45° to the extrusion direction (45ED) and perpendicular to the extrusion direction (PED), prismatic &lt;a&gt; slip contributes little to the texture evolution. (2) When the sample is compressed along three different directions, pyramidal &lt;c+a&gt; slip leads to the grain being deflected toward the normal direction (ND), and the {10-12} extension twin deflects the grain at a large angle. (3) When only the {10-11} compression twin is activated, the grain will be deflected in the ND while the sample is compressed along the ED and 45ED, but when the sample is compressed in the PED, the grains are concentrated from both sides of the ED to the center.

In-situ observation of microstructure and orientation evolution of the Cu–Cr–Zr-Hf alloys

The roles of Hf element in the mechanical properties, deformation mode and orientation evolution of the Cu-0.4Cr-0.2Zr-0.2Hf (wt.%) alloys were investigated using both ex-situ and in-situ electron backscatter diffraction (EBSD). The results indicate that the trace Hf element (0.2 wt%) addition into the Cu–Cr–Zr alloys motivates the multiple slip activities. The activation of multiple slip systems indirectly or directly influences the tensile strength, strain distribution and lattice rotation. Firstly, it promotes the generation of dislocations, and thus enhances the work hardening rate, contributing to the improvement of the ultimate tensile strength. Secondly, it inhibits the movement of dislocations to the grain boundaries, and thus hinders the strain localization at the grain boundaries, promoting the homogeneous deformation. Thirdly, the interaction between dislocations on different slip systems restricts the intragranular lattice rotation, leading to the high stability of the grains with Goss orientation in the Cu–Cr–Zr-Hf alloys. The mutual transform between the R-CubeRD orientation and Goss orientation is also observed. This study deepens the understanding of deformation mechanisms and texture evolution of the Cu–Cr–Zr-Hf alloys.

Experimental study on tensile deformation behaviors under room and elevated temperatures induced by microstructure inhomogeneity of ZK60 Mg with a longitudinal weld

The tensile tests of the extruded ZK60 Mg containing a longitudinal weld seam were carried out at room and elevated temperatures, and the effects of induced microstructure inhomogeneity on tensile deformation behavior was clarified. The results show that the deformation mode, dynamic recrystallization (DRX), texture evolution and mechanical properties are strongly affected by the longitudinal weld seam, temperature, and loading direction. The room temperature (RT) deformation of welding zone is controlled by the dislocation slips with the association of some twins, while twinning plays significant roles in the accommodation of c-axis strain of the coarse grains on matrix zone. The deformation at RT stretched along extrusion direction (ED) and transverse direction (TD) are controlled by basal slip/twinning and basal slip/prismatic slip/twinning, respectively. During high temperature tension, the dislocation cross slip of pyramidal slip is activated, and grain boundary sliding occurred in welding zone, leading to the superplastic behavior. With the increase of tensile temperature, the predominant DRX mode is transformed from continuous DRX to discontinuous DRX. Moreover, the basal poles of the grains spread from TD towards ED with the decrease of maximum pole intensity when stretched along ED, while non-basal textures are transformed to 〈10–10〉 fiber texture when stretched along TD. The slip-dominated flow is seen during RT tension along ED, while twinning becomes predominant during RT tension along TD. The fine grain structure causes the superior RT tensile properties along ED of welding zone with ultimate tensile strength of 315 MPa and elongation to failure of 13.8%. With the increase of tensile temperature, the slipping-dominated deformation is transformed into twinning-dominated, causing the decrease of strength and increase of elongation.