Crystallographic Texture Research Articles

Enhanced steel machining performance using texture-controlled CVD alpha-alumina coatings: Fundamental degradation mechanisms

Cemented carbide inserts coated with CVD α-alumina, particularly those exhibiting a (0001) texture, have proven highly effective in steel turning. Despite the established superior performance of (0001) textured alumina coatings, the underlying reasons remain unclear. This study explores the influence of the crystallographic texture of alumina on wear mechanisms in various chip-tool contact zones on the insert rake face. The objective is to establish a fundamental understanding of the active degradation mechanisms and machining performance by relating coating texture to the orientation and deformation of individual Al2O3 grains. Two multilayered coatings, Al2O3 on Ti(C,N), featuring (0001)- and (112‾0)-textured CVD α-alumina, were assessed in dry turning of a bearing steel. The wear rate of the (112‾0) coating was double that of the (0001) coating. Worn coatings exhibit nano-terrace formation at the insert edge, likely due to chemical etching. In the sticking zone, plastic deformation leads to larger facets for grains oriented with the chip flow direction, while rounded surfaces result if this condition is not met. In the transition zone, both (0001) and (112‾0) textured coatings undergo increased plastic deformation accompanied by sub-surface dislocations. (0001) texture deforms more by basal slip creating a wavy coating pattern with steps present at larger misalignments of the lattice planes in neighboring grains while (112‾0) texture deforms by several slip systems creating elongated ridges and ruptured-like areas resulting in rougher surface. This difference in surface morphology is then inherited by the abrasion of submicron coating fragments embedded in the chip (more in (112‾0) texture) in the sliding zone resulting in an even rougher surface. Chemical reaction with the hot chip may also contribute to wear acting as an additional mechanism. This fundamental understanding contributes to the potential enhancement of steel machining using texture-controlled CVD alumina coatings, ultimately improving coated cutting tool performance.

Behavior of microstructure and mechanical properties in the stir zone of friction stir welded ME21 magnesium alloy

In this work, Friction Stir Welding (FSW) of magnesium alloy ME21 in a T-profile is performed with a relatively higher welding speed than usual in this material. The FSW process parameters, i.e., rotational speed and welding speed, are investigated focused within its inherent microstructural and mechanical properties on the stir zones of the welded joints. The concept of a Stribeck Curve in tribological systems, is transferred to FSW to explain the transition between insufficient and full plasticization of the material. The stir zone presented a strong grain refinement due to the activation of dynamic recrystallization along with a completely changed crystallographic texture and orientation due to FSW. The hardness is overall improved, while the ductility and tensile strength were reduced. The microstructure and texture in the stir zone were not strongly influenced by changes in the welding parameters.

Advances in Fatigue Performance of Metal Materials with Additive Manufacturing Based on Crystal Plasticity: A Comprehensive Review.

Using metal additive manufacturing processes can make up for traditional forging technologies when forming complex-shaped parts. At the same time, metal additive manufacturing has a fast forming speed and excellent manufacturing flexibility, so it is widely used in the aerospace industry and other fields. The fatigue strength of metal additive manufacturing is related to the microstructure of the epitaxially grown columnar grains and crystallographic texture. The crystal plasticity finite element method is widely used in the numerical simulation of the microstructure and macro-mechanical response of materials, which provides a strengthening and toughening treatment and can reveal the inner rules of material deformation. This paper briefly introduces common metal additive manufacturing processes. In terms of additive manufacturing fatigue, crystal plasticity simulations are summarized and discussed with regard to several important influencing factors, such as the microstructure, defects, surface quality, and residual stress.

Special interlayer pause strategy for controlling grain morphology and tensile property anisotropy of TC11 alloys fabricated by directed energy deposition technology

Directed energy deposition (DED)-built titanium alloys have long suffered from the anisotropic mechanical properties induced by the long columnar prior β grains growing along the building direction, which restricts their applications. In this work, a special interlayer pause (SIP) strategy is designed to reduce the tensile property anisotropy by adjusting the grain morphology. The grain morphologies, microstructure, crystallographic texture, tensile properties and their anisotropy of DEDed TC11 titanium alloys were systematically investigated. The results show that the SIP strategy promotes the columnar-to-equiaxed transition of grain morphology, reduces grain sizes, and weakens the crystallographic textures. The microstructure of SIP samples consists of superfine basketweave and lamellar α laths and residual β phases. The average length of α laths increases with the SIP layer number. In addition, the maintained superfine α phases contribute to an ultrahigh yield strength of ∼1200 MPa of the SIP samples. The yield strength of the horizontal direction gradually decreases and that of the vertical direction increases with increasing the SIP layer number, resulting in a lowered strength anisotropy of less than 2%. When adopting an optimal SIP strategy, the as-deposited TC11 alloy exhibits a relatively small ductility anisotropy.

Effect of Tool Geometry on the Microstructure of Friction Stir Welding of Copper and 316L Stainless Steel

The microstructure evolution during dissimilar friction stir welding of copper with stainless steel 316L is studied. The welding is performed in transparence configuration using tools of two different geometries. The joints are characterized by optical microscopy, scanning and transmission electron microscopy, electron backscattered diffraction, and microhardness. The microstructure and crystallographic texture of base metals are significantly affected. The joint produced using a shoulder of 8 mm in diameter is characterized by a copper nugget with refined grains. The texture of copper is dominated by component of the shear texture. The steel beneath the tool shows a grain refinement with grains of sub‐micron size and a texture which is close to the ideal simple shear texture. For the joint produced by the 16 mm diameter tool shoulder, the nugget consists of large grains of copper, while the steel beneath the tool shows small recrystallized grains of micrometer size. The texture in the steel is dominated by the component of the shear texture. The Cu/316L interface in both types of joint is of very good quality. In a detailed study of the interface, it is revealed that the welding of metals is achieved by mutual intense mechanical interlocking without formation of any intermetallic compounds.

Analysis of Phase-Specific Strain Pole Figures for Duplex Steels under Elasto-Plastic Uniaxial Tension—Experiment vs. EPSC Modelling

For the duplex stainless steel X2CrNiMoN22-5-3, phase-specific strain pole figures (strain PFs) for the phases ferrite (bcc) and austenite (fcc) were analysed under uniaxial tensile loading for various loading states in purely elastic and elasto-plastic regimes. Experimentally, strain PFs were determined by means of in situ neutron diffraction strain measurements under defined uniaxial loading. These experimental results were compared with strain PFs calculated using elasto-plastic self-consistent (EPSC) modelling. The comparison was performed for two different {hkl} planes per phase. While classic load stress and load partitioning analyses for multi-phase materials are often limited to the load direction and a selected direction transverse to it, the results illustrate the added value of determining a strain PF, especially when a phase-specific texture is present. The comparison with experimental data shows how well the load partitioning behaviour can be predicted using common EPSC models, using the example of a duplex stainless steel. The EPSC model used was validated with the software ISODEC in its elastic range. Based on the results of the EPSC model, and taking into account the local phase-specific crystallographic texture, a prediction can be made as to what extent intergranular stresses and phase-specific textures could affect the results of a (residual) stress analysis by means of the diffraction method. This makes it possible to assess whether, for technical applications, meaningful residual stress results can be expected in certain component directions.

Effect of hot rolling mode on crys-tallographic texture and mechanical properties of directly quenched bainitic steel

The paper considers the effect of hot rolling mode on the structure, mechanical properties and crystallographic texture, as determined by EBSD, for a directly quenched thick plate of high strength bainitic steel. According to the obtained results, stronger strain hardening of austenite before the phase transformation leads to appearance of granular bainite and hence diminishes the final steel strength.

Compressive mechanical response and microstructures in low strain rate plastic deformation of stainless steel 316L fabricated by selective laser melting

Characterization of the mechanical properties plays an essential role in the post-processing and evaluation of the functionality of the additively manufactured metallic parts. A number of studies have been focused on the tensile properties of additively manufactured metals. However, the quasi-static compression test of the additively manufactured 316L blocks with different heat-treatment conditions and scanning strategies seems to be overlooked in the literature. This paper aims to provide a comprehensive study of compressive mechanical response in plastic deformation of SS316L fabricated by selective laser melting (SLM). The mechanical response and microstructures in compressive deformation is analyzed for three printing strategies with 0°-, 90°- and 67.5°- scanning and three heat treatment conditions (450 °C for 3 h, 1100 °C for 1 h with furnace cool and 1100 °C for 1 h with water quenching) for selective laser melted (SLMed) stainless steel 316L in comparison with wrought stainless steel 316L in this work. Alteration of mechanical properties, microstructure evolution and compressive deformation mechanism is studied. Melt pool features are not significantly affected by low-temperature heat treatment (450 °C for 3 h) but fully dissolved through high-temperature heat treatment (1100 °C for 1 h). High-temperature heat treatment provides a higher resistance to compressive plastic deformation for SLMed 316L compared with the low-temperature heat-treated and as-built samples where more twinnings are observed. The compressive plastic deformation mechanism of 90°- and 67.5°-scanning samples is similar, which mainly results from twinning-induced plasticity. For 0°-scanning samples, the strong crystallographic texture is the main cause of anisotropic deformation. Modelling and simulation have been conducted to explain the anisotropic deformation mechanism of the 0°-scanning strategy. Simulation results suggest that the morphology difference of laser-scanning tracks and melt pools, which leads to material flow along the laser scanning direction, explains the anisotropic deformation mechanism.

Investigation of Microstructures and Tensile Properties of 316L Stainless Steel Fabricated via Laser Powder Bed Fusion.

In this study, a thorough investigation of the microstructures and tensile properties of 316L stainless steel fabricated via laser powder bed fusion (L-PBF) was done. 316L stainless steel specimens with two different thicknesses of 1.5 mm and 4.0 mm fabricated under similar conditions were utilized. Microstructural characterization was performed using optical microscopy (OM) and scanning electron microscopy (SEM) equipped with electron backscatter diffraction (EBSD). Melt pools and cellular structures were observed using OM, whereas EBSD was utilized to obtain the grain size, grain boundary characteristics, and crystallographic texture. The 1.5 mm thick sample demonstrated a yield strength (YS) of 538.42 MPa, ultimate tensile strength (UTS) of 606.47 MPa, and elongation to failure of 69.88%, whereas the 4.0 mm thick sample had a YS of 551.21 MPa, UTS of 619.58 MPa, and elongation to failure of 73.66%. These results demonstrated a slight decrease in mechanical properties with decreasing thickness, with a 2.4% reduction in YS, 2.1% reduction in UTS, and 5.8% reduction in elongation to failure. In addition to other microstructural features, the cellular structures were observed to be the major contributors to the high mechanical properties. Using the inverse pole figure (IPF) maps, both thicknesses depicted a crystallographic texture of {001} <101> in their as-built state. However, when subjected to tensile loads, texture transitions to {111} <001> and {111} <011> were observed for the 1.5 mm and 4.0 mm samples, respectively. Additionally, EBSD analysis revealed the pre-existence of high-density dislocation networks and a high fraction of low-angle grain boundaries. Interestingly, twinning was observed, suggesting that the plastic deformation occurred through dislocation gliding and deformation twinning.

Tailoring heat treatment for AlSi7Mg0.6 parts with as-built surface generated by laser powder bed fusion to reduce surface roughness sensitivity

The most important advantage of additive manufacturing by laser powder bed fusion (PBF-LB) technique is the ability to produce geometrically complex parts, but the problem is their rough surfaces, often difficult or inaccessible to finish by machining. Therefore, research to improve the reproducibility of the mechanical behavior of parts manufactured from aluminum alloy powders with as-built surfaces is of vital importance for the aerospace and automotive industries. Since local notches occurring on rough surfaces after the PBF-LB process are unavoidable, the way to solve this problem is to obtain as-built surfaces of the highest possible quality and to adapt a post-process heat treatment that increases the ductility and fracture toughness of the material. To this end, the present work focused on the study of the mechanical performance of AlSi7Mg0.6 samples with a rough as-built surface in the as-built state and after several variants of post-process heat treatment, combined with a detailed analysis of the microstructures corresponding to these states. Tensile samples built on a platform preheated to 100 °C, achieved a relative density of 99.85%, satisfactory surface quality, a relatively low level of residual stress and moderate crystallographic texture. Despite the rough surface, the samples under the as-built condition and after different variants of heat treatment (direct aging (DA), stress relieving (SR), and solution annealing followed by artificial aging (T6)), achieved tensile properties comparable to those reported in the literature for PBF-LB samples with machined surfaces. The resulting combinations of tensile properties of PBF-LB samples after different heat treatment variants were evaluated using the quality index (QI) commonly used to assess the quality of heat-treated Al-Si-Mg castings. It was found that the proposed T6 treatment provides the best combination of strength properties and ductility, compared to those obtained after both DA and SR, as well as after T6 treatment of high-quality castings, from the point of view of reducing the sensitivity of AlSi7Mg0.6 alloy to surface roughness.

Grain Morphology and Mechanical Properties Tailoring of Inconel 625 Alloy Fabricated by Laser Powder Bed Fusion

The controlling strategies of grain morphology and mechanical properties of Inconel 625 alloy by laser powder bed fusion are investigated, and beyond that, the effects of phase composition, grain morphology, and crystallographic texture on mechanical properties are also studied. The phase evolution is insensitive to the scanning strategies, and all of the samples are composed of γ‐Ni phase. The (001) texture orientation tends to increase with the scanning rotation angle, and the sample IV fabricated by scanning strategies of 90° shows the highest (001) texture. Different grain morphologies can be tailored by controlling the direction of heat flow between continuous layers via changing scanning strategies. The proportion of large elongated columnar crystals gradually decreases, while the proportion of the equiaxed grains gradually increases as the scanning strategies change from 0°→90→67°→45°. The rotation angle increases from 0° to 45°, and the ultimate tensile strength and yield strength increase from 1267 ± 12 to 1304 ± 5 MPa and 760 ± 10 to 801 ± 5 MPa, respectively, which is attributed to the different stress states presented in the columnar crystals and the equiaxed crystals.

Texture Exposure of Unconventional (101)Zn Facet: Enabling Dendrite‐Free Zn Deposition on Metallic Zinc Anodes

AbstractTexturing metallic zinc anodes (MZAs) for selective exposure of (002)Zn plane with high thermodynamical stability is an efficient scheme for dendrite‐free Zn electrodeposition. However, fundamental factors that influence Zn deposition morphology via surface crystallographic texture engineering are not well understood. Herein, different from traditional cognition, MZAs with preferential exposure of (101)Zn facet are demonstrated to be equally effective in promoting dendrite‐free Zn deposition, which is enabled by introducing trace amount (0.01 m) of theophylline into ZnSO4 electrolyte. Experimental results and mathematical model corroborate, indicating mechanistically that the theophylline derived cations preferentially adsorb on the (002)Zn crystal plane due to higher adsorption energy, thereby accelerating its growth through increased binding affinity with Zn2+ ions. Consequently, this phenomenon facilitates the texture exposure of (101)Zn facet to achieve ordered surface crystallographic orientation of MZAs (101‐Zn), thus enabling electrodeposition/dissolution cycling over 650 h under a depth of discharge up to 40% and significantly boosting the rechargeability (76.7% capacity retention after 1000 cycles) of the 101‐Zn||carbon‐cloth@MnO2 full battery relative to counterpart without theophylline additive (36.3%). The work offers deep insights on the scientific links between the surface crystallographic orientation of MZAs and Zn deposition morphology, while opens up vast untapped opportunities to realize dendrite‐free MZAs.

Predicting the in-plane mechanical anisotropy of 7085 aluminum alloys through crystal plasticity simulations and machine learning

The crystallographic texture of rolled 7xxx series aluminum alloys may lead to mechanical properties anisotropy which undermines the formability and performance of the material. This article aims to explore the quantitative relationship between texture and the in-plane anisotropy of 7085 aluminum alloy. A comprehensive computational method combining crystal plasticity simulation with machine learning and experiment was used to establish an analytical model and train a machine learning model to predict the anisotropy of 7085 aluminum alloys. We first performed a full-field crystal plasticity spectral simulations using fast Fourier transformation (CPFFT) to predict the anisotropy of 7085 aluminum alloy at different annealing times. Then, based on the CPFFT simulation data, the quantitative relationship between texture and the in-plane anisotropy of the r-value was established by using the multiple linear regression and gradient boosting regressor model. The results indicate that CPFFT simulation can effectively capture the influence of texture changes on anisotropy, and the model established through the gradient boosting regressor model is in good agreement with experimental results, providing effective guidance for improving the performance of 7085 aluminum alloy sheets.

An investigation over microstructure and HIP processing effects on wear performance of pure chromium parts fabricated by laser powder bed fusion

Chromium (Cr) and its alloys have long been valued for their exceptional properties, including corrosion resistance and high-temperature stability, rendering them indispensable in industrial applications such as chemical processing, energy production, and aerospace. However, due to the difficulties in Cr-based alloy manufacturing, there is a need for novel manufacturing methodologies. Additive Manufacturing (AM) emerges as a promising approach, particularly Laser Powder Bed Fusion (LPBF), which allows for intricate designs, reduced material waste, and simplified assembly. However, certain issues still need to be addressed, including defects like cracks and porosities in the manufactured parts. Post-processing techniques such as Hot Isostatic Pressing (HIP) have gained prominence for enhancing the material properties and quality of AM parts, including those produced using LPBF. HIP treatments are effective in eliminating internal pores, although some challenges remain, notably the presence of trapped argon and grain coarsening side effects of HIP process parameters. This study focuses on LPBF-processed pure chromium parts with crystallographic texture and investigates their properties after HIP treatment, including microstructure, hardness, and tribological performance. According to the obtained results: the HIP process reduced cracks, especially in the center region, but increased gaps in the side region. HIP also hindered grain realignment, limiting grain growth, and resulting in high HAGB density and low MUD values. Elevated HIP processing pressure negatively affected tribological performance due to increased grain size, and reduced hardness. This study, for the first time, realized the effect of HIP conditions on the microstructure and tribological performance of LPBF-processed pure Cr.

Effect of Build Geometry and Porosity in Additively Manufactured CuCrZr

Abstract The current work presents an understanding of microstructure and mechanical properties as a function of build geometry and build orientation in Cu-Cr-Zr via the laser powder bed fusion (LPBF) technique. Porosity, microstructure, and mechanical properties have been compared in as-printed (AP) and heat-treated (HT) LPBF Cu-Cr-Zr, between cylindrical and cube geometries, along the longitudinal (L) and transverse (T) build orientations. Varying porosity levels were observed that yielded parts with 96–97% relative density in the AP condition. The AP microstructure demonstrated a hierarchical microstructure, comprising grains (2.5–100 μm) with a cellular substructure (400–850 nm) and intracellular nanoscale (20–60 nm) precipitates. Unlike most materials in the AP condition, crystallographic texture was found to be absent; however, very distinct river-like patterns highlighted a novel feature of the LPBF Cu-Cr-Zr. Upon solutionizing and aging, Cr precipitates were seen heterogeneously nucleating along cell boundaries (0.5–1.3 μm), causing up to 45% enhancement in the strength and a 4–5% lower ductility. The yield strength along the transverse orientation was 10–16% higher than that of longitudinal orientation, in both the AP and HT conditions. Fracture surface of the tensile samples exhibited micro-voids, cleavage facets, and unmelted particles. Despite the porosity, overall mechanical properties matched well with those obtained in nearly dense (&amp;gt;99%) samples and the mechanical property debit was less than 10%.

Dislocation structure evolution during room temperature dwell loading of a Ti-6Al-4 V alloy

The current work examines the evolution of the dislocation structure, within both the α and β phases, of a Ti-6Al-4 V alloy subjected to room temperature dwell loading performed at about 96% of the macroscopic yield stress level for several durations, as part of a synchrotron in-situ deformation experiment. The obtained findings represent a vital contribution to creating a scientific basis for improving lifing predictions for aero-propulsion components. The dislocation configuration, type and density were examined post-mortem using transmission electron microscopy (TEM). Despite the relatively low applied stress level, well-developed dislocation structures were already formed within the α phase at a dwell duration of 10 min and changed only modestly up to 60 min. The plastic deformation of the above phase took place solely via dislocation slip. To facilitate a comparison between different dwell durations, the TEM investigation focused on the regions oriented for the prismatic glide that represented the main deformation mode due to the starting crystallographic texture. After deformation, the regions oriented for the prismatic slip contained planar slip bands largely consisting of dislocations of a screw type. There was rather limited interaction between different bands, as the dislocation arrays passed through the slip band intersections with only minor difficulty. The screw-type dislocations seemed to preferentially form during straining. Dislocation Burgers vectors experimentally determined within the β phase occasionally departed from the Schmid rule and such dislocations typically showed a prevalent screw component. Some deformation banding and {112} 〈111〉 − type mechanical twin formation were locally detected within the β phase.

Stability of crystallographic texture and mechanical anisotropy toward Al2O3/YAG eutectic ceramic composite using single crystalline seeds

During the directional solidification of Al2O3-based eutectic ceramic composites, crystallographic orientation control is a promising method for tailoring the performances of composite parts. However, despite its importance in the fabrication of texture-controlled structural parts, the stable growth of the eutectic crystallographic texture for long distance (growth distance from 30 mm to 120 mm) in ceramic composite system is not widely understood. Herein, the competition and stability of crystallographic texture for Al2O3/YAG eutectic ceramic composite induced by different seeds using the Czochralski (CZ) technique were investigated. When the eutectic composites induced by different single crystalline Al2O3 seeds, coarse Al2O3 particles and uniform eutectic structure appeared alternately below the seeds. While the eutectic ceramic composite induced by YAG seed has a memory effect on the stability of its microstructure and morphology. We demonstrated that the eutectic ceramic composites induced by the ⟨112‾0⟩ Al2O3 and ⟨101‾0⟩ Al2O3 seeds could stably inherit the seed orientation and grow as a single crystallographic texture with a low interfacial strain (<10 %). In particular, the stable evolution of crystallographic texture depended not only on the type of seeds but also on the mutual constraint of eutectic coupling growth. Furthermore, the nano-hardness, elastic modulus, and compressive strength (1600 °C) of the composites induced by different seeds have anisotropic characteristics. However, the bending strength was not sensitive to the change of crystallographic texture. It could maintain excellent high temperature stability, which was approximately 265–316 MPa from room temperature to 1600 °C. These results promote the development of high-performance Al2O3-based eutectic ceramic composites with anisotropic design using seeding technique to tailor their crystallographic texture.

The use of diffraction techniques for understanding structure–property relationships in Heusler alloys

Heusler compounds are intermetallic alloys that are capable of a wide range of unique properties such as magnetocaloric, thermoelectric, and magnetic-shape-memory effects, antiferromagnetism, superconductivity, and they can even act as topological insulators. These multifunctional behaviors make Heusler alloys prime candidates for numerous smart device applications. However, their specific properties critically depend on their crystalline structures, chemical order, structural phase transformations, and crystallographic texture. Thus, as compositions and processing parameters are varied it becomes essential to be able to accurately characterize the structure of these materials at various scales. This paper provides a brief review of diffraction-based characterization techniques ideally suited for the characterization of Heusler alloys with examples from our previous works including use of synchrotron, neutron, and electron diffraction, especially as a function of temperature and/or magnetic field to explain important phenomena demonstrated by Heusler alloys.

Evolution of Microstructure and Crystallographic Texture in Deformed and Annealed BCC Metals and Alloys: A Review

Dislocation slips, twinning, shear banding (SBs), strain localization, and martensite formation are a few deformation modes that are activated in BCC metals and alloys. Strain, strain rate, and deformation temperature are other parameters that determine the activation of deformation modes in BCC alloys. This review focuses on several BCC alloys, such as beta-titanium (β-Ti), tantalum (Ta), and ferritic stainless steels (FSSs), all of which exhibit differences in deformation behavior. These alloys often undergo thermo-mechanical processing (TMP) to enhance their mechanical properties. TMP leads to the evolution of deformation-induced products, such as SBs, strain-induced martensite (SIM), strain localizations, and mechanical/deformation twins (DTs) during plastic deformation, while also influencing crystallographic texture. The deformation modes in β-Ti depend upon the stability of the β-phase (i.e., β-stabilizers); low-stability alloys show the formation of SIM along with slips and twins, whereas in highly stable β-Ti alloys, only slip+twin modes are observed as the primary deformation mechanisms. In the case of Ta, slip activity predominantly occurs on {110} planes, but it can also occur on planes with the highest resolved shear stress. The breakdown of Schmid’s law or non-Schmid behavior for Ta and Ta-W alloys has been discussed in detail. The cold rolling (CR) of FSSs results in the formation of ridges, which is an undesirable phenomenon leading to very low formability. The microstructures of the rolled sheets consist of elongated ferrite grains with in-grain SBs, which are preferentially formed in the γ-fiber-oriented grains. The formation of finer grains after recrystallization improves both the mechanical properties and ridging resistance in FSS. Therefore, this review comprehensively reports on the impact of TMP on the microstructural and crystallographic texture evolution during the plastic deformation and annealing treatment of β-Ti, Ta alloys, and FSSs in BCC materials, using results obtained from electron microscopy and X-ray diffraction.

The mechanics of the friction-assisted lateral extrusion process

The friction-assisted lateral extrusion process (FALEP) is gaining attention as a candidate for fabricating high-performance ultrafine grain alloys for potential industrial applications. It consists of extruding metal in bulk or powder form into a solid sheet in a single operation to obtain ultrafine-grained (UFG) structures. The sheet has high yield strength due to its UFG microstructure and a shear-type crystallographic texture that is fundamentally different from the textures of sheets obtained by rolling. Apart from its single-step feature, FALEP requires lower forces than in rolling, so less energy is required to achieve large reductions. The present work introduces analytical elastic/plastic continuum calculations for the mechanics of the FALEP process. The results of the calculations demonstrate the great advantages of FALEP with respect to rolling and equal/non-equal channel angular pressings.Graphical