Texture Evolution Research Articles

Microstructure, Texture Evolution and Mechanical Characteristics of Ultrafine-Grained Structure in Friction Stir Processed Aluminum Alloys

Microstructure, Texture Evolution and Mechanical Characteristics of Ultrafine-Grained Structure in Friction Stir Processed Aluminum Alloys

On the Relationship between Thermomechanical Processing Parameters and Recrystallization Texture in AA1100 Aluminum Alloy

In this study, 48 hot-rolling processing conditions were designed to investigate the influences of thermomechanical processing parameters on the recrystallization behavior and texture development. The hot-rolling experiments were conducted using the thermomechanical simulator Gleeble 3800 at temperatures of 275, 300, and 350 °C with strain rates of 5 and 90 s−1 up to 60 and 85% reduction. The microstructure and texture analysis were measured by using the EBSD technique on a large area. Experimental results show that the Cube component maintains a volume fraction between 10% and 20%, below the 40% recrystallization fraction, but the volume fraction of Cube significantly increases between 20% and 50% above the 40% recrystallization fraction. However, the fractions of Rotated Cube (RC) and Goss components remain below 10%.

Texture and bendability evolution mechanism of 6063 aluminum alloy tube formed by free-bending technology employing cross-scale numerical modeling

With the improvement of application requirements, the combination of precise shape and high performance of tube components has become a burning issue. This work investigates the free-bending process of 6063 aluminum alloy tubes using cross-scale numerical modeling. The cross-scale framework integrates macroscopic finite element model (FEM) and crystal plasticity finite element model (CPFEM) through strain history. CPFEM exhibits excellent agreement with the macroscopic FEM and experimental results for both the Mises stress and texture evolution. Predictions indicate that as bending deformation increases, the volume fractions of the initial Cube texture decrease, while the Goss texture component increases. The overall texture strength continuously decreases. Meanwhile, slip mode plays a critical role in texture evolution, causing similar trends in the inner and outer bend regions. Additionally, the findings from the cross-scale simulation accurately predict the detailed texture evolution of the 6063 aluminum alloy tube under various feeding speeds. The development of Goss texture in various forming regions and the formation of substructures within Goss-oriented grains are primary factors contributing to reduced tube formability, which could illustrate the primary mechanisms for variation in tube bendability effectively. The proposed cross-scale method lays the foundation for research on complex spatial tube components as well. Moreover, cross-scale simulation facilitates the prediction of macroscopic deformation and microstructural evolution in critical regions of tube components, allowing for the optimization of bending processes based on cross-scale simulation results.

Observation of competing interactions and field-induced ferromagnetism in noncentrosymmetric cubic Nd3Te4 lattice

Unconventional magnetism is key to advancement in a variety of spintronic applications and thus needs to be explored in new materials. Here, we report the in-depth magnetic studies of noncentrosymmetric Nd3Te4 and findings support the existence of Dzyaloshinskii-Moriya interaction in addition to symmetric exchange interaction among the moments. The large magnetic irreversibility with negative magnetization in M(T) data and associated first-order magnetic transition in isothermal magnetization data suggest the competing interactions resulting in multiple magnetic phases. The gradual evolution of magnetic texture has been probed by changes in the magnetization entropy having interesting characteristics like the inverse magnetocaloric effect. Most importantly, we have probed the existing nontrivial magnetic phase under a low applied magnetic field by ac-χ(T, H) and dc magnetization (M − H) data, having the same critical field in both measurements. The existence of multiple magnetic phases which are interconnected through first-order field-induced magnetic phase transitions have been probed at low field. The transition from paramagnetic to field-induced state for larger applied fields follows a second-order.

Understanding the mechanism of bimodal texture evolution and DRX behavior of AZ31 magnesium alloy during shear deformation

Shear deformation in commercial magnesium alloys frequently resulted in an additional atypical texture where the basal plane aligned nearly parallel to the extrusion direction, affecting the alloy's mechanical anisotropy. This study prepared AZ31 magnesium alloys with both typical shear texture and atypical texture using a two-stage shear method at 250 °C, 290 °C, and 340 °C. The formation mechanism of the bimodal texture and their relationship with dynamic grain refinement and deformation parameters were comprehensively investigated. While temperature-dependent activation of <c+a> slip usually contributed to the atypical texture, this study identified a {101¯2} twin associated microstructure that reinforced the abnormal texture at lower processing temperature. It was found that the abundant nucleation of the multi-orientation {101¯2} twin bands in the initial stage and their differential slip activations facilitated the evolution of an alternating banded structures characterized by bimodal texture. These microstructures inherited the grain boundary rotation axis of {101¯2} twin and was potentially assimilated into specialized θ[112¯0] symmetric tilt grain boundaries with lower interface energy during continuous shear, stabilizing the bimodal texture. During shear deformation, grain nucleation strengthened the [101¯0]−[112¯0] fibers with bimodal texture by generating ∼30°[0001] grain boundaries through the preferential accumulation of prismatic dislocations. However, more continuous dynamic recrystallization, discontinuous dynamic recrystallization, and micro-shear bands facilitated the nucleation of grains with dispersed basal orientations via dominant non-prismatic dislocations, weakening the overall texture. Besides, the mechanical anisotropy of the alloys was comprehensively influenced by atypical texture and microstructure. At higher deformation temperatures, the reduction in twinning bands and the increase in dynamic recrystallization level relieved the alloy’s tension-compression asymmetry, but deprived its yield strength. This study supplemented the formation mechanisms of bimodal texture during shear deformation, providing valuable insights for optimizing wrought magnesium alloys with superior mechanical properties.

A comparative study of microstructure and texture evolution in low cost titanium alloy swarf and powder recycled via FAST and HIP

A comparative study of microstructure and texture evolution in low cost titanium alloy swarf and powder recycled via FAST and HIP

Investigations on the influence of hot rolling on the creep characteristics of additively manufactured Mg-5Ag alloy

The requirement for lightweight materials that can survive increasingly severe conditions for aerospace components has fueled the research on magnesium alloys. The current work investigates the influence of hot rolling on the creep characteristics of the Mg-5Ag alloy that is fabricated through a selective laser melting process. The creep properties of parent material (PM) and hot-rolled specimens (HRA) are determined by indentation creep tests at 250 °C, 275 °C, and 300 °C. The microstructural evolution, phase transformation kinetics, and texture evolution were deduced using instrumental analysis, including SEM, EBSD, TEM, and XRD. The specimen PM features α-Mg grains with intermetallic Mg-Ag particles along grain boundaries and random grain orientations with low-angle boundaries. However, specimen HRA has a more fraction of Mg-Ag precipitates, a dominant (0001) grain orientation, and higher peak intensity from the (002) plane. The HRA specimen also demonstrates higher apparent activation energies, attributed to microstructural changes from hot rolling. The results show that the creep resistance of the hot rolled Mg-5Ag alloy is superior to as-fabricated Mg-5Ag alloy based on the creep velocity, stress exponent, and apparent activation energy.

Texture and lattice strain evolution in a pearlitic steel during shear deformation: An in situ synchrotron X-ray diffraction study

In-situ synchrotron X-ray diffraction experiments were conducted on the pearlitic steel sample with a carbon content of 0.74% by weight. Specimens were subjected to uniaxial loading that induced shear deformation and two-dimensional diffraction patterns were acquired. The evolution of the lattice microstrain and the strain-resolved crystallographic texture development of both ferrite (α-BCC) and cementite (θ-orthorhombic) phases were followed. The analysis revealed that the texture changed from {110}<113>α to {113}<121>α component and then, stabilized at {013}<uvw>α orientations. The θ phase exhibited a weak texture in the {100, 010, and 001}θ family planes. Additionally, it was revealed that the nucleation of interfacial defects at the α/θ interface promotes the amorphization of cementite and the activation of slip systems in less densely packed {310}α planes. The influence of microstructural changes on mechanical properties is discussed.

Effect of intermediate annealing temperature and cold rolling deformation on the texture of yttrium bearing oriented silicon steel

The cold rolling and intermediate annealing process, along with the incorporation of rare earth elements, play an important role in the microstructure, texture, and inhibitors of oriented silicon steel. Currently, there is limited research on the impact of rare earth yttrium on texture evolution during the cold rolling and intermediate annealing processes. Therefore, the effects of different cold rolling deformations and intermediate annealing temperatures on the microstructure and texture of Y bearing oriented silicon steel have been studied. The experimental results demonstrate that the average grain size of the intermediate annealed plate progressively decreases with increasing the cold rolling deformation. This is because the high cold rolling deformation brings more additional dislocations and distortions, consequently enhancing the driving force for recrystallization. Observing the microstructure with various cold rolling deformation, the results show that the annealed plate with a 72 % reduction rate exhibited the highest Goss texture percentage of 4.83 %. This is because the cold-rolled sheet with a reduction rate of 72 % exhibits an abundance of Goss oriented substructures. These substructures quickly dominate the {111}<112> deformed matrix during the initial recrystallization, and promote grains nucleation and growth. As the annealing temperature increases, the driving force for the growth of recrystallized grains also increases, leading to a gradual increase in grain size. The plate annealed at 940 °C exhibits the highest percentage (4.83 %) of Goss texture. The addition of rare earth Y can lead to an increase in grain size in the intermediate annealed plate and facilitate the formation of {411}<148> texture. This is advantageous for the abnormal growth of Goss texture. The results demonstrate that a cold rolling deformation rate of 72 % and an intermediate annealing temperature of 940 °C are good for promoting abnormal growth of Goss orientation. The study results on precipitation kinetics suggests that the grain boundary nucleation of AlN and dislocation nucleation of MnS are the most effective way of nucleation. The precipitates in oriented silicon steel without Y are Al2O3 and MnS, while those in the samples with Y are AlN, YS, and YOxSy. The addition of rare earth Y leads to a reduction in both the density and size of precipitates. Moreover, With the increase of annealing temperature, the size of precipitates decreases and the amount of precipitates increases. Additionally, the addition of Y makes the steel more clean, meanwhile, the pinning effect of inclusions on grain boundaries is weakened. Therefore, the grain size of the steel with Y is larger.

Experimental and crystal plasticity finite element study of dynamic shear behavior of CoCrNiSi0.3 medium-entropy alloy

Single-phase CrCoNi-based medium-entropy alloys (MEAs) have garnered considerable attention as a promising class of metallic materials. However, despite this growing interest, the dynamic mechanical response of CrCoNi-based MEAs at high strain rate remains controversial. The dynamic shear mechanical behavior of CoCrNiSi0.3 was characterized through Hopkinson-bar experiment utilizing hat-shaped specimen. In this study, a damage model based on the maximum shear strain of each slip system was chosen to describe the damage initiation and evolution. Combined with this micro-scale damage and dislocation density-based crystal plasticity theory, two constitutive models were proposed to perform predictions of the dynamic shear behavior of CoCrNiSi0.3. The strain rate effect, adiabatic temperature rising, damage evolution, and twin volume fraction during dynamic shear deformation were tracked by investigating the influence of resolved shear stress, dislocation density, texture evolution, and twinning systems shear strain. The presented model effectively predicts the deformation state of specimen, the formation and evolution of Adiabatic Shear Bands (ASBs), and the variations in strain rate and temperature at different locations within the shear region. Adiabatic Shear Bands and texture evolution are caused by the local dislocation density rising and misorientation distributions.

Microstructural and Textural Evolution in Hexagonal Close-Packed Metals: The Case of Zirconium, Magnesium, and Titanium

Microstructural and Textural Evolution in Hexagonal Close-Packed Metals: The Case of Zirconium, Magnesium, and Titanium

Revealing the deformation behavior of graphene nanosheets (GNSs) reinforced copper matrix laminated composites via Viscoplastic Self-Consistent (VPSC) modeling

Constructing a laminated structure in metal matrix composites working as a promising approach to simultaneously enhance strength and toughness. Nevertheless, the deformation behavior of individual grains within such laminated composites remains largely unexplored. In this study, graphene nanosheets (GNSs) reinforced copper (Cu) matrix laminated composites were fabricated through electrophoretic deposition, vacuum hot-press sintering, and hot rolling. The mechanical properties were examined via room temperature tensile testing, while microstructure and texture evolution were investigated quasi-in-situ using SEM-EBSD and neutron diffraction techniques. Additionally, Visco-plastic Self-Consistent (VPSC) modeling was utilized to simulate texture evolution during tension, shedding light on the deformation mechanisms within the laminated GNSs/Cu composites. The findings revealed that the grains in the GNSs/Cu laminated composites deformed independently without accommodating strains of grains in adjacent Cu layers. This deformation mode was further confirmed by observations on the RD-ND plane of the fractured GNSs/Cu sample. The insights garnered from this study elucidate the deformation mechanism of laminated GNSs/Cu composites and offer valuable guidance for optimizing the design of advanced metal matrix composites.

Effect of interlayer scan rotation on structure-property relationship of directed energy deposited CoCrNi medium entropy alloy

Laser-based Additive Manufacturing (AM) is sought to be a prevalent technique to synthesize medium to high entropy alloys. However, the anisotropy, temperature distribution, and residual stresses in Laser-based AM are some of the major problems that need to be addressed. The effect of interlayer scan rotation on microstructure, texture evolution, and tensile properties of laser-based directed energy deposited CoCrNi are investigated in this study. The electron backscatter diffraction studies revealed the strong 〈001〉 cubic crystallographic texture along the build direction (YZ-plane) without scan rotation. However, there is no preferred grain orientation observed with interlayer scan rotations. The 〈111〉 fiber texture and 〈111〉〈101〉 fiber texture, respectively, are obtained with 67° and 90° scan rotation strategies. The randomized grain orientation due to fiber texture formation enhanced strength significantly with little improvement in ductility. In addition, the substructure refinement is also observed after incorporating scan rotation. Moreover, the present work suggests that nearly isotropic strength and elongation are obtained with 67° rotations.

Effect of scanning strategy and laser peening on microstructure and fatigue properties of laser-directed energy deposition-built 15-5 PH stainless steel

PurposeThe aim of this paper is to study the effect of laser shock peening (LSP) on mechanical behaviour of the laser-directed energy deposition (LDED)-based printed 15-5 PH stainless steel with U and V notches. The study specifically concentrates on the evaluation of effect of scan strategy, machining and LSP processing on microstructural, texture evolution and fatigue behaviour of LDED-printed 15-5 PH steel.Design/methodology/approachFor LSP treatment, 15-5 PH steel was printed using LDED process with bidirectional scanning strategy (XX [θ = 0°) and XY [θ = 90°]) at optimised laser power of 600 W with a scanning speed of 300 mm/min and a powder feed rate of 3 g/min. Furthermore, LSP treatment was conducted on the V- and U-notched fatigue specimens extracted from LDED-built samples at laser energy of 3.5 J with a pulse width of 10 ns using laser spot diameter of 3 mm. Post to the LSP treatment, the surface roughness, fatigue life assessment and microstructural evolution analysis is performed. For this, different advanced characterisation techniques are used, such as scanning electron microscopy attached with electron backscatter diffraction for microstructure and texture, X-ray diffraction for residual stress (RS) and structure information, Vicker’s hardness tester for microhardness and universal testing machine for low-cycle fatigue.FindingsIt is observed that both scanning strategies during the LDED printing of 15-5 PH steel and laser peening have played significant role in fatigue life. Specimens with the XY printing strategy shows higher fatigue life as compared to XX with both U- and V-notched conditions. Furthermore, machining and LSP treatment led to a significant improvement of fatigue life for both scanning strategies with U and V notches. The extent of increase in fatigue life for both XX and XY scanning strategy with V notch is found to be higher than U notch after LSP treatment, though without LSP samples with U notch have a higher fatigue life. As fabricated sample is found to have the lowest fatigue life as compared to machines and laser peened with both scan strategies.Originality/valueThis study presents an innovative method to improve the fatigue life of 15-5 PH stainless steel by changing the microstructure, texture and RS with the adoption of a suitable scanning strategy, machining and LSP treatment as post-processing. The combination of preferred microstructure and compressive RS in LDED-printed 15-5 PH stainless steel achieved with a synergy between microstructure and RS, which is responsible to improve the fatigue life. This can be adopted for the futuristic application of LDED-printed 15-5 PH stainless steel for different applications in aerospace and other industries.Graphical abstract

Electropulsing-induced recrystallization of cold-rolled SUS304 and effects of duration on mechanical properties

A cold rolled SUS304 stainless steel was treated by electropulsing treatment (EPT) with different time and duration, and then, microstructural evolution and texture development was studied by electron backscattering diffraction (EBSD) technique. EPT enhances the recrystallization process of cold rolled SUS304 stainless steel and the completed recrystallization state of sample can be obtained at low temperature below 530 K for a short time of 100 s. The best strength-ductility combination can be obtained when 210 μs of pulse duration applying. Pulse duration has been found to have a significant impact on the microstructure and tensile properties of SUS304. EPT is not a simple heat treatment process and electrical effects should be responsible for the recrystallization of the EPT samples.

Texture development of pure Ti by rolling at various temperatures and its effect on sheet formability

This work investigated the effect of rolling temperature (25–800 °C) on rolling-texture development and sheet formability of pure Ti. The rolling temperature significantly affected the development of the typical transverse-direction (TD)-split basal texture in pure Ti sheet by altering the tilting angle of (0001) basal poles. Notably, a normal-direction (ND) basal texture, where the tilting angle of (0001) basal poles was approximately 0°, developed at an intermediate rolling temperature of 400 °C. This result is remarkable because the ND basal texture is rare in pure Ti. Formation of this unusual ND basal texture was attributed to significant activation of basal <a> slip. In contrast, a typical TD-split basal texture was dominant at the other rolling temperatures. Formation of this typical texture was attributed to pyramidal <c+a> slip. After subsequent recrystallization annealing, sheet formability was examined. Despite their different textures, the sheets previously rolled at the different rolling temperatures showed similar formability. This similarity occurred because any given texture could not simultaneously provide in-plane stretching uniformity and thinning capability during sheet forming. The present study suggests an important guidance for modifying texture of pure Ti sheets to effectively increase their formability.

Study on the abnormal growth of goss oriented grains in Fe-3.2%Si steel: Role of thermomechanical processing and inhibitors

Detailed characterization of Fe-3.2%Si steel after different stages of processing trails including hot-rolling, normalization annealing, cold-rolling with intermediate annealing, and finally, decarburization/primary annealing and secondary annealing has been carried out. The evolution of ferrite grain structure, grain boundary characteristics, and the micro-texture of the samples are characterized using electron backscatter diffraction (EBSD). The inhibiting precipitates such as MnS and CuS are studied under scanning and transmission electron microscopy (SEM and TEM). The evolution of ferrite grain structure and texture are explained considering the mechanisms (role of inhibitors, crystal orientation, special boundary, high energy medium angle boundary, grain boundary curvature) responsible for the abnormal growth of Goss oriented grains after final annealing treatment. Extremely coarse Goss oriented grains (as large as >20 mm) have been developed in this study. An analytical approach is presented at the end to explain the texture evolution during processing considering the Taylor factor maps (for different loading conditions) and the prediction of limiting ferrite grain size for abnormal grain growth, considering the size and fraction of the precipitates along with their coarsening and dissolution kinetics.

Research on the evolution law of aggregate micro-texture during long-term wearing of asphalt pavement

The micro-texture of aggregates plays a very important role in anti-skid performance of asphalt pavement. Three kinds of aggregates, limestone, basalt and sandstone, were used to prepare asphalt mixture to study the evolution law of micro-texture of aggregates under long-term wear. One Third Scaled Model Mobile Load Simulator (MMLS) was used to conduct wear tests on asphalt mixtures under two working conditions: drying and water immersion. Laser confocal scanning microscopy (LCSM) was used to test and analyze the micro-texture evolution of the original aggregate, mixed aggregate, and accelerated loaded aggregate surfaces. The mechanism of texture evolution was analyzed based on the mineral composition, Vickers hardness, and micro-structure of the aggregate. The results show that wear can lead to varying degrees of polishing of the aggregate micro-texture, with limestone>basalt>sandstone, and the drying condition is more severe than the water immersion condition. The wear degree of the texture is closely related to the mineral composition and hardness of the aggregate. The more complex the mineral composition, the greater the hardness and hardness dispersion, the less likely the texture will be polished. The micro-texture indexes Ra and Rq have the highest correlation with anti-skid performance, and the relationship between them is obtained by fitting. Scanning electron microscopy (SEM) shows that the fine particles in sandstone are easy to fall off, which is conducive to the regeneration of texture, and is also the internal reason for its best anti-skid durability.

Research on microstructure and properties enhancement of TiN/GH5188 Co-superalloy composite fabricated by laser powder bed fusion

Improving mechanical properties effectively in Laser Powder Bed Fusion (LPBF) is a substantial challenge. Utilizing metal matrix composites with customizable TiN nanoparticle proportions presents an efficient strategy for fabricating high-strength LPBF parts. This study employed LPBF to fabricate TiN/GH5188 Co-based superalloy composites with alternative TiN nanoparticle contents (0, 0.5, 1, and 1.5 wt%). The effect of nano-TiN particles on the microstructure, texture evolution, and mechanical properties of TiN/GH5188 composites was investigated. Notably, the presence of nano-TiN acts as a reinforcing particle, facilitating the precipitation of the BCC strengthening phase, resulting in substantial strength enhancement. As the TiN content increases, the yield strength and microhardness consistently rise. At a 1.5 wt% TiN addition, a significant enhancement is observed, with yield strength rising by 22.0 % and microhardness increasing by 16.9 %. Although the aggregation of TiN precipitates into larger particles reduces ductility, the appropriate addition of TiN can effectively mitigate the microstructural anisotropy and induce a transition in the texture toward a non-preferred orientation, while maintaining high strength and ductility. A TiN/GH5188 composite containing 1 wt% TiN exhibits a yield strength and tensile strength of 822.4 MPa and 1131.8 MPa, respectively, accompanied by a microhardness of 334.3 HV. The elongation remains at 29.3 %, while exhibiting a non-preferred orientation (111) texture. Compared to GH5188, the yield strength, tensile strength and microhardness are increased by 17.6 %, 7.2 % and 12.1 %, respectively. This study demonstrates the significance of LPBF in producing high-performance TiN/GH5188 Co-superalloy composites and elucidates the potential mechanisms of TiN in improving microstructure and enhancing properties.

Unravelling dynamic recrystallisation in a microalloyed steel during rapid high temperature deformation using synchrotron X-rays

Microstructure evolution during high-strain rate and high-temperature thermo-mechanical processing of a 44MnSiV6 microalloyed steel is investigated using in situ synchrotron high-energy powder X-ray diffraction. The conditions selected replicate a newly developed near solidus high-strain rate process designed for reducing raw material use during the hot processing of steels. High temperatures (exceeding 1300 °C) and high strain rate ε˙ = 9 s-1 processing regimes are explored. The lattice strains and dislocation activity estimated from diffraction observations reveal that the microstructure evolution is primarily driven by dynamic recrystallisation. A steady-state stress regime is observed during deformation, which develops due to intermittent and competing work hardening and recovery processes. The texture evolution during the heating, tension, shear deformation and cooling stages is systematically investigated. The direct observation of phase evolution at high-temperature and high-strain rate deformation enables a comprehensive understanding of new manufacturing processes and provides deep insights for the development of constitutive models for face-centred cubic alloys.