Shear Texture Research Articles

Analysis of microstructure evolution and deformation mechanism of nano-oxides Al2O3 dispersion strengthened copper alloy during compression at room temperature

The refinement of grains to the size of ∼ 600 nm is observed in a nano-scaled Al2O3 dispersion-strengthened (ODS) Cu alloy under compression distortion. The plastic deformation mechanism of the ODS Cu alloy is studied by the observation and analysis of the evolution of grain size, dislocation density and distribution, and texture orientation during compression process. The deformation process can be divided into four stages, i.e., leaner deformation stage, plastic-strengthening transition stage, relative steady state stage and softening stage under ∼ 90 % compression, according to the stress-strain curves. The grains are found split into refined sub-grains by the net-like entangled dislocations due to the pinning effect of nano-scaled Al2O3 particles. The dislocation density of ODS Cu is found increasing within 30 % compression, and then remaining to a plateau under ∼ 30 %−60 % compression, but then under ∼ 60 %−80 % and ∼ 80 %−90 % compression, the dislocation density increases firstly and then decreases. The crystal orientation is transformed from the Goss texture {110}< 001 > to the inhomogeneous Shear texture {001}< 110 > during the compression process, due to the rotation of grains. This study provides a further understanding of the strengthening mechanism and a guidance for the design of ODS Cu alloys, which is significant for the prospective future structural applications.

Nano-structuring of a high entropy alloy by severe plastic deformation: Experiments and crystal plasticity simulations

The evolution of microstructure, texture, and mechanical properties of an induction melted non-equiatomic Al6Co23.5Fe23.5Mn23.5Ni23.5 (at.%) high entropy alloy subjected to severe plastic deformation was investigated experimentally and by simulations. Analyses using electron backscatter diffraction and transmission Kikuchi diffraction images revealed the evolution of the microstructures. The coarse-grained initial structure was deformed down to an average grain size of 50 nm after a shear strain of 11 by employing the high-pressure compressive shearing process, at room temperature. Transmission electron microscopy analysis showed the presence of nano-twins. The high deformation led to a significant increase in the strength, up to ≈ 1.0 GPa. X-ray diffraction macro-texture analysis revealed a shear texture with the dominance of the B/B¯{112}110-type component whose intensity varied with strain. A two-step Taylor-type polycrystal plasticity simulation approach reproduced the texture by a correlation value of 91%. In the first part of the modeling, grain fragmentation was simulated, while in the second part, grain boundary shearing and deformation twinning were considered together with the operation of {111}112-type partial slip. The effect of twinning was also examined in the texture modeling and the simulations estimated that its fraction was less than 2%.

Overcoming the strength-ductility trade-off in additive manufactured AlSi10Mg plates by friction stir welding at a low rotational speed

The main problem in post-treatment of laser powder bed fusion (L-PBF) AlSi10Mg is the sharp reduction in strength when the ductility enhances, i.e. the problem of strength-ductility trade-off. Friction stir welding (FSW) at a low rotational speed of 200 rpm was employed to join AlSi10Mg plate produced by laser-powder bed fusion in conjunction with overcoming the strength-ductility trade-off. The microstructure, texture, and mechanical properties of the as-built and friction stir welded samples were examined. FSW resulted in the elimination of porosities, formation of ultrafine-grains with an average grain size of 0.7 μm, increment in dislocation density and Taylor factor, and fragmentation of Si particles. In addition, after FSW, B/B¯ and C shear texture components were mainly formed in the center of the stir zone, while at the shoulder-dominated zone the A1∗(111)[1¯1¯2] and A2∗(111)[112¯] components might be formed. The main grain structure formation mechanism was continuous dynamic recrystallization occurring by a gradual increase in misorientation of low angle grain boundaries and geometrically dynamic recrystallization. Consequently, tensile elongation was enhanced by ≈173%, while a negligible decrease in strength (≈9%) was observed. During tensile loading, the joint was fractured from the stir zone by the initiation of cracks from the surface of the sample, resulting in a bimodal dimple structure.

Unveiling the ductility enhancement mechanisms in AZ31 magnesium alloy achieved via shear strain-assisted twin orientation regulation

The ductility enhancement mechanisms were investigated in AZ31 magnesium alloy based on the newly proposed concept of shear strain-assisted twin orientation regulation (SATOR). The simple shear strain was imposed on pre-twinned samples with various strain levels to rotate the twin orientation. The results indicated that the fracture strain of SATORed samples with the greatest ductility improvement was ∼1.5 times higher than that of the original material. Overall shear-deformed samples generated a bimodal fine-grained structure. While the preferred texture of the as-received alloy was only deviated by ∼12° during shear deformation, the pre-twinned samples obtained a closed-45° shear texture. Furthermore, combining the simulation results of the visco-plastic self-consistent (VPSC) model, the improved ductility is mostly ascribed to the efficient regulation of initial twin orientation, the promoted basal slip activity, and bimodal fine-grained structure. The SATOR method has been proved to be a promising strategy for dramatically increasing ductility while also providing the reference required for texture control via twin orientation regulation in Mg alloys.

Frictional contact mechanics of asymmetric soft textures

Soft textures with asymmetric friction properties in shear against soft substrates have significant promise for many applications, particularly in the medical field. Here, we fabricate textures with directional friction properties and investigate the interaction between soft textures and soft substrates in shear. We experimentally determine that shear direction, texture stiffness, and presence of a lubricant affect coefficient of friction. Finite element models support experimental results and suggest underlying mechanisms. For soft, directional textures sheared against soft untextured substrates, unlubricated friction is primarily governed by adhesion and contact area while lubricated friction is primarily governed by a plowing effect of texture into the substrate.

Friction Stir Welding of AA5754-H24: Impact of Tool Pin Eccentricity and Welding Speed on Grain Structure, Crystallographic Texture, and Mechanical Properties.

This study investigates the effect of tool pin eccentricity and welding speed on the grain structure, crystallographic texture, and mechanical properties of friction stir welded (FSWed) AA5754-H24. Three tool pin eccentricities of 0, 0.2, and 0.8 mm at different welding speeds ranging from 100 mm/min to 500 mm/min and a constant tool rotation rate of 600 rpm were investigated. High-resolution electron backscattering diffraction (EBSD) data were acquired from each weld's center of the nugget zone (NG) and processed to analyze the grain structure and texture. In terms of mechanical properties, both hardness and tensile properties were investigated. The grain structure in the NG of the joints produced at 100 mm/min, 600 rpm, and different tool pin eccentricities showed significant grain refining due to dynamic recrystallization with average grain sizes of 18, 15, and 18 µm at 0, 0.2, and 0.8 mm pin eccentricities, respectively. Increasing the welding speed from 100 to 500 mm/min further reduced the average grain size of the NG zone to 12.4, 10, and 11 µm at 0, 0.2, and 0.8 mm eccentricity, respectively. The simple shear texture dominates the crystallographic texture with both B¯/B texture component with the C component at their ideal positions after rotating the data to align the shear reference frame with the FSW reference frame in both the PFs and ODF sections. The tensile properties of the welded joints were slightly lower than the base material due to the hardness reduction in the weld zone. However, the ultimate tensile strength and the yield stress for all welded joints increased by increasing the friction stir welding (FSW) speed from 100 to 500 mm/min. Welding using the pin eccentricity of 0.2 mm resulted in the highest tensile strength; at a welding speed of 500 mm/min, it reached 97% of the base material strength. The hardness profile showed the typical W shape with a reduction in the hardness of the weld zone and a slight recovery of the hardness in the NG zone.

Multipass Friction Stir Processing of Laser-Powder Bed Fusion AlSi10Mg: Microstructure and Mechanical Properties.

The effect of multipass friction stir processing (FSP) on the microstructure and mechanical properties of an AlSi10Mg alloy produced by laser-powder bed fusion was investigated. FSP was performed at a rotational speed of 950 rpm and traverse speed of 85 mm/min. The results indicated that FSP destroyed the coarse grain structure in the as-built AlSi10Mg by generating fine and equiaxed grain structures with shear texture components of A1*(111)[1¯1¯2] and A2*(111)[112¯], in addition to causing fragmentation and refinement of the Si networks. FSP reduced the tensile strength slightly but significantly improved ductility. One-pass FSP exhibited superior mechanical properties compared with the two- and three-pass scenarios. The higher strength of the one-pass sample was attributed to the strengthening mechanisms induced by the Si particles, which were grown by repeated FSP. The higher ductility of the one-pass sample was explained using the kernel and grain average misorientations. Furthermore, the post-FSP microstructural evolution and fracture behavior of the samples were discussed.

Investigating the Effect of Various Sous-Vide Cooking Conditions on Protein Structure and Texture Characteristics of Tilapia Fillet Using Synchrotron Radiation-Based FTIR.

The effects of various sous-vide (SV) cooking conditions (50-60℃, 30-60 min) on physicochemical properties related to the texture characteristics, protein structure/degradation, and sensory acceptability of tilapia fillet (Oreochromis niloticus) were investigated. With an increasing temperature and processing time of SV cooking, protein degradation (of both myofibrils and connective tissue) was more pronounced, as evaluated by the decrease in water- and salt-soluble proteins, total collagen, as well as the changes in the ratio of secondary protein structures (α-helix, β-sheet, β-turn, etc.), which were determined by synchrotron-FTIR (SR-FTIR). These degradations were associated with the improvement of meat tenderness, as estimated by shear force and texture profile analyzer (TPA) results. Among all SV conditions, using 60 ℃ for 45 min seems to be the optimal condition for tilapia meat, since it delivered the best results for texture characteristics and acceptability (p < 0.05). Moreover, principal component analysis (PCA) results clearly demonstrated that the highest texture-liking score of this condition was well associated with the intensity of β-sheets, which seem to be the crucial component that affected the texture of SV-cooked tilapia more so than other parameters. The findings demonstrated the potential of SR-FTIR to decipher the biomolecular structure, particularly the secondary protein structure, of SV-cooked tilapia. This technique provided essential information for a better understanding of the changes in biomolecules related to the textural characteristics of this product.

Grain Structure Formation and Texture Modification through Multi-Pass Friction Stir Processing in AlSi10Mg Alloy Produced by Laser Powder Bed Fusion.

A new strategy is proposed to modify the grain structure and crystallographic texture of laser-powder bed fusion AlSi10Mg alloy using multi-pass friction stir processing (FSP). Accordingly, 1-3 passes of FSP with 100% overlap were performed. Scanning electron microscopy and electron backscattered diffraction were used for microstructural characterization. Continuous dynamic recrystallization and geometric dynamic recrystallization are the governing mechanisms of grain refinement during FSP. The stir zones have bimodal grain structures containing large and fine grains. The multi-pass FSP caused a considerable increase in the volume fraction of the large-grained area in the stir zone, which contained higher values of low-angle boundaries and sharp shear texture components of B(11¯2)[110] and B¯(1¯12¯)[1¯1¯0]. The formation of low-energy grain boundaries in the stir zone and alignment of the low-energy crystallographic planes with the surface of the sample made the strategy of using multi-pass FSP a promising candidate for corrosion resistance enhancement in future studies. Moreover, the detailed evolution of the grains, texture components, grain boundaries, and Si particles is discussed.

- Invited Review - Factors affecting beef quality and nutrigenomics of intramuscular adipose tissue deposition.

Beef quality is characterized by marbling (marbling degree and marbling fineness), physiochemical (shear force, meat color, fat color, texture, and maturity), and sensory (tenderness, flavor, juiciness, taste, odor, and appearance) traits. This paper summarizes and addresses beef-quality characteristics and the beef-grading systems in Korea, Japan, the USA, and Australia. This paper summarizes recent research progresses on the genetic and nutritional factors that affect beef quality. Intramuscular (i.m.) adipose tissue deposition or marbling is a major determinant of beef quality. This paper addresses the mechanisms of i.m. adipose tissue deposition focused on adipogenesis and lipogenesis. We also address selected signaling pathways associated with i.m. adipose tissue deposition. Nutrients contribute to the cellular response and phenotypes through gene expression and metabolism. This paper addresses control of gene expression through several nutrients (carbohydrates, fat/fatty acids, vitamins, etc.) for i.m. adipose tissue deposition. Several transcription factors responsible for gene expression via nutrients are addressed. We introduce the concept of genome-based precision feeding in Korean cattle.

Rolling-sliding contact fatigue failure and associated evolutions of microstructure, crystallographic orientation and residual stress of AISI 9310 gear steel

In the present study, rolling-sliding contact fatigue (RSCF) failures of AISI 9310 gear steel were analyzed systematically, in terms of characterizing the fatigue life, evolution of microstructure and crystallographic orientation, and variation of microhardness and residual stress distributions. The RSCF experiments were conducted using a twin rollers fatigue test rig. The RSCF life of AISI 9310 steel roller decreased continuously with increasing the maximum Hertzian contact pressure, however, it could be effectively improved by additional shot peening process owing to the enhanced microhardness and compressive residual stress near the roller surface. The main fatigue damage characteristics near the roller surface were consisted of inclined cracks, micropitting, spallation and plastic deformation. Although the compressive residual stress was reduced by RSCF, there was an obvious increase in the microhardness which should be attributed to the refined microstructure, increased dislocation density as well as phase transformation from retained austenite to martensite. In addition, the accumulated plastic strain during RSCF resulted into development of several preferred crystallographic orientations corresponding to ideal shear texture components of body-centered cubic (BCC) materials that has been seldom reported.

Stability and deviations from the cube texture during rolling and annealing of Ni foil

Formation of the {100}<001> cube texture component has been reported extensively in many heavily deformed face-centered cubic (FCC) metals and alloys after annealing. The present study shows how to avoid the formation of strong cube texture on the surface of high-temperature annealed Ni foils subjected to large rolling reductions and also retain the high intensity of twin boundaries. The evolution of the surface texture of rolled and annealed foils are discussed in comparison to conventional rolling, shear, and recrystallization texture components. The stability of the cube and ND-rotated cube components in rolled foils are elaborated. In spite of discontinuous recrystallization mechanisms, a high fraction of rolling texture components is retained after annealing. Suppression of the cube component after annealing has been attributed to the constricted-annealing process and possible activation of low-energy twin boundaries. Annealing twins were found to form during the recrystallization process via a growth fault mechanism.

Using the Proteolytic Properties of the Biomass of Lactic Acid Microorganisms to Create New Food Products

Introduction. Lactic acid microorganisms are widely used in the production of lactic acid foods, including for the creation of new products with functional properties. The ability of some types of lactic acid organisms to produce proteolytic enzymes can be used in other food industries, in particular in the meat industry. This issue has not been studied enough in the scientific literature. Purpose. The purpose of this work is to substantiate the feasibility of using biomass of lactic acid microorganisms — producers of proteolytic enzymes to modify the properties of hard meat raw materials. Materials and Methods. The paper monitors the scientific literature on the use of proteolytic enzymes in the food industry and in the production of animal feed, on the influence of various factors on the properties of enzymes, the dependence of food quality on the state of the protein component. Experiments were carried out on the cultivation of microorganisms — producers of proteolytic enzymes and their effect on meat raw materials. Results . The efficiency of using subsurface serum for the cultivation of a consortium of microorganisms is shown. The efficiency of using the obtained biomass for processing hard meat raw materials is shown. Conclusion . As a result of such processing, meat raw materials have acquired improved functional and technological properties (maturation time, moisture binding ability, water retention ability, shear stress limit, texture, and color of meat), which allows the use of modified raw materials for the production of new meat products with good consumer properties (taste, aroma, tenderness of meat product, protein digestibility). In addition, proteolytic enzymes are a protective factor against many unfavorable microorganisms.

Decoupling the effects of texture and composition on magnetic properties of Fe-Si sheet processed by shear deformation

Soft magnetic Fe-Si alloys (electrical steels) possess exceptional functional properties such as high permeability, low coercivity, and low core loss, which generally improve with increasing Si content in the alloy. However, Fe-Si alloys containing > 3.5 wt% Si are also characterized by prohibitively low workability and poor ductility that have prevented their efficient commercial production in sheet form by rolling. This has limited their use for improving efficiency of motors and transformers. In this study, hybrid cutting-extrusion (HCE) is used as a single-step thermomechanical processing method to produce continuous Fe-Si alloy sheet with high Si compositions of 4 wt% to 6.5 wt%. HCE sheet is shown to have a homogeneous annealed grain structure and simple-shear crystallographic textures. By controlling the HCE deformation path, varied crystallographic shear textures are created in the sheet. Quasi-static magnetic properties of the HCE sheet are evaluated to decouple the effects of sheet texture and Si composition on resultant permeability and coercivity properties. The results suggest that HCE, with suitable process scaling, is a viable route for production of high-Si content electrical steel sheet for next-generation motors and transformers.

Dislocation density and shear texture effects on grinding force during the grinding of maraging steel 3J33

This paper focuses on the change of dislocation density and shear texture generated in plastic deformation, and its effect on the grinding force during the grinding of maraging steel 3J33. The grinding force in a grinding arc is divided into three stages, i.e., rubbing, plowing and chip forming in turn, and each grinding arc is continuous. The large plastic deformation caused by the forming force of cutting has a significant effect on the nearest rubbing force in the next arc area by influencing the microstructure. However, it has little effect on the plowing force away from the cutting area. Therefore, a flow stress model with respect to the influence of dislocation density and texture was established to describe the relationship between the grinding forces of different grinding arcs and modify the total grinding force. The microstructure of the processed materials before and after grinding experiments was compared, and the corresponding shear texture, Taylor factor and dislocation density were analyzed. The analysis of the multi-stage forces composed elastic deformation and plastic deformation of offers a comprehensive understanding of dislocation density and shear texture evolution mechanisms during the grinding process that would be very beneficial for process optimization. At high wheel speed, lower workpiece speed and cutting depth could result in higher rubbing force, thereby achieving better polishing effect and lower surface roughness.

Microstructure, texture, and mechanical properties correlation of AA5083/AA6061/SiC composite fabricated by FSAM process

The current study deals with the effect of silicon carbide (SiC) particle reinforcement on the microstructure, texture evolution, and mechanical properties of the AA5083-O/AA6061-T6 build fabricated using the friction stir additive manufacturing (FSAM) process. The stir zone (SZ) of particle reinforced build shows ultra-fine grain refinement (av. size of 4.22 μm) in comparison to AA5083 (41 μm) and AA6061 (43 μm) base metals. The extent of grain refinement is possible due to the uniform dispersion of SiC particles in the matrix accompanied by dynamic recrystallization (DRX) driven by particle-stimulated nucleation (PSN) and the Zener-Holloman mechanism. Weak texture intensities were visible for both reinforced/unreinforced cases due to reheating and re-stirring action at the joint interface. Major shear texture components (B/ B‾, and C) with the presence of recrystallization texture components cube {001} <101>, P {011} <112>, rotated cube (H) {001} <110> and F {111} <112> were noted in SiC reinforced build, suggesting the DRX at the joint interface. SZ of SiC reinforced build consists of an average microhardness of 116 ±4HV0.1 which is 1.2 times higher than the average microhardness of unreinforced build (96 ±3HV0.1). The maximum strength of 291 MPa was noted for AA5083/AA6061/SiC composite, which is appreciably higher than the unreinforced case (197 MPa).

Comparison of microstructure, texture, and mechanical properties of the SQ and thread pin profile FSW joint of AA6061-T6 with Al2O3 particle reinforcement

The paper presents the effect of flat and thread pin profiles on friction stir welding (FSW) of 6061-T6 aluminium alloy with particle reinforcement. The thread geometry on the tool pin enhances the material mixing and improves the material flow in the plastic state. However, in the flat tool pin, the plasticized material was stuck to the side faces of the tool pin surface. The microstructural analysis of the weld specimen revealed that the powder particles were agglomerated in the stir zone (SZ) region in the square tool pin case. However, the powder particles were homogeneously dispersed in the SZ region when the welding was done with the threaded tool pin profile tool. The tensile and hardness tests were also conducted to check the flat and threaded cylindrical pin weld specimen's joint strength and hardness variation. The Electron backscattered diffraction (EBSD) analysis revealed that the average (Av.) grain size of the SZ region of the TCT and SQ pin are 3.74 µm and 5.64 µm, and the fraction of high angle grain boundaries are 0.560 and 0.368, respectively. The texture analysis of the SZ region revealed that the major availability of the shear texture component B/ B ̅ and C in the TCT pin weld specimen.

Phase Transformation Induced by High Pressure Torsion in the High-Entropy Alloy CrMnFeCoNi.

The forward and reverse phase transformation from face-centered cubic (fcc) to hexagonal close-packed (hcp) in the equiatomic high-entropy alloy (HEA) CrMnFeCoNi has been investigated with diffraction of high-energy synchrotron radiation. The forward transformation has been induced by high pressure torsion at room and liquid nitrogen temperature by applying different hydrostatic pressures and large shear strains. The volume fraction of hcp phase has been determined by Rietveld analysis after pressure release and heating-up to room temperature as a function of hydrostatic pressure. It increases with pressure and decreasing temperature. Depending on temperature, a certain pressure is necessary to induce the phase transformation. In addition, the onset pressure depends on hydrostaticity; it is lowered by shear stresses. The reverse transformation evolves over a long period of time at ambient conditions due to the destabilization of the hcp phase. The effect of the phase transformation on the microstructure and texture development and corresponding microhardness of the HEA at room temperature is demonstrated. The phase transformation leads to an inhomogeneous microstructure, weakening of the shear texture, and a surprising hardness anomaly. Reasons for the hardness anomaly are discussed in detail.

Effect of rotation speed on microstructure and mechanical anisotropy of Al-5083 alloy builds fabricated by friction extrusion additive manufacturing

The final builds with multiple layers for a non-age-hardenable aluminum alloy were successfully fabricated under different rotation speeds using friction extrusion additive manufacturing, a force-controlled friction-based additive manufacturing process that allows the free design of the deposition path. The single layer thickness increased from 1.7 mm to 3.0 mm when the rotation speed was reduced from 800 r/min to 400 r/min for a given layer thickness of 4 mm. The grain size at the interface was refined to 3.8–5.0 μm at 800 r/min because less recrystallization occurred, resulting in a higher geometrically necessary dislocations density. The grains formed at the interface at 800 r/min were mainly determined by recrystallization textures Cube, CubeRD, and CubeND and deformation texture S. However, a stronger coupling effect between heat and plastic deformation at 600 r/min leads to the dominance of shear textures B/B‾ and RtCu and deformation textures S. The final deposits superior to the wrought Al alloy 5083-H112 in terms of tensile properties were obtained at 600 r/min due to the largest contribution of grain refinement strengthening. Grain refinement increases strength at the interface and interlayer by 113.1 MPa and 92.1 MPa, respectively. The tensile strength, yield strength, and elongation at break in the Z direction reach 290.2 MPa, 163.3 MPa, and 12.6%, respectively. Due to the existence of kissing bonding at 800 rpm, the value of the elongation at break in the Z direction is only 19% of the value in the X direction.

Microstructure, texture, and mechanical properties of asymmetrically cold-rolled Ni1.5FeCrCu0.5 high-entropy alloy

This study deals with the microstructural evolution, texture development, and mechanical properties of the cold-rolled and annealed Ni1.5FeCrCu0.5 high-entropy alloy (HEA). In addition to symmetric rolling (SR), asymmetric rolling (AR) was performed with different velocity ratios (VRs) between the working rolls. Electron backscatter diffraction (EBSD) measurements showed that the grain size of the annealed samples was drastically reduced by increasing the VR of the rolls and imposing shear strain. Moreover, annealing was associated with forming a high volume fraction of annealing twins. Recovery was accelerated by increased accumulated shear strain through the thickness of the ARed strips. The X-ray diffraction (XRD) method was employed to investigate the crystallographic texture in the processed high-entropy alloy. Macrotexture data revealed that the intensity of E {111} <110> and F {111} <112> shear texture components were remarkably higher in the ARed sheets. However, the intensities of S {123} <634> and Copper {112} <111> orientations were decreased in favor of the Brass {011} <211> component, indicating the pure-metal to alloy type texture transition in low stacking fault energy (SFE) materials. Compared to the homogenized sample, the Cube {001} <100> component was dramatically weakened by the annealing of the cold-rolled specimens. In terms of the mechanical properties, the pronounced grain refinement of the post-roll annealed strips enhanced the yield strength (YS) and ultimate tensile strength (UTS) from 332 to 503 in the homogenized condition to 625 and 709 MPa in the asymmetrically rolled (ARed) sample with a velocity ratio of 8. Finally, plastic anisotropy analysis demonstrated that the sheet drawability was gradually improved by increasing the velocity ratio due to the increased mean r-values and reduced planar anisotropy (Δr) values.