Recrystallization Texture Research Articles

Study of strength-ductility and anisotropic behavior of Mg-Gd-Y-Zn-Zr alloy prepared by Equal channel double angular pressing

In the present work, the Mg-Gd-Y-Zn-Zr alloy was processed by Equal channel double angular pressing (ECDAP). The evolution of microstructure and mechanical properties are systematically investigated. The results demonstrate that the strength and ductility after ECDAP can be simultaneously enhanced, which is due to the generation of dynamic recrystallization and unique basal texture with dispersive circular distribution. The anisotropy behavior is also evaluated by the compression testing along different direction. After ECDAP for 4 passes, the anisotropy degree is effectively decreased compared with the sample after ECDAP for 1 pass. Moreover, the deformation behavior during ECDAP process is determined by prismatic slip.

Enhancement of {110}<001> Texture by Controlling α‐phase and Achievement of Low Young's Modulus and High Strength in Metastable β‐type Ti–Zr‐Based Alloys

Achieving both low Young's modulus and high strength, which are essentially in a trade‐off relationship, is an important challenge in the field of biomaterials. Herein, the effects of oxygen and nitrogen addition on mechanical properties and recrystallization texture of a metastable Ti–18Zr–3Nb–3Sn–2Mo alloy are investigated. Both oxygen and nitrogen additions increase the apparent yield stress and tensile strength. The N‐added alloy exhibits an exceptionally strong {110}<001> texture, commonly referred to as Goss texture, leading to a lower Young's modulus when compared with the O‐added alloy. It is found that the formation and subsequent dissolution of the α‐phase plays an important role in the development of recrystallization texture. The {110}<001> texture can be enhanced in the O‐added alloy by a two‐step heat treatment, the first step to form the α‐phase and the second step to dissolve the α‐phase during recrystallization. An excellent combination of a low Young's modulus and a high yield stress is achieved in the O‐added alloy subjected to the two‐step heat treatment.

Evolution of microstructure and tensile behavior in an interstitial strengthened high entropy alloy

The microstructural evolution and mechanical properties of Fe61.5Cr17.5Ni11.5Al8C1.5 high-entropy alloys (HEAs) were investigated to establish an optimal set of annealing conditions that would result in reasonable recrystallized fractions across the different temperatures and durations. The evolution of the microstructure was analyzed, tracking the transformation from the rolling texture to the recrystallization texture, as well as any phase transformations that occurred. The grain size distribution, overall microstructural features, and the effects of annealing temperature and time on the tensile properties of the HEAs were examined and discussed. The alloy was subjected to cold rolling and subsequent annealing treatments, revealing a single FCC phase after homogenization at 1260 °C. The cold-rolled samples retained the FCC structure at lower annealing temperatures (400 °C and 500 °C) but underwent a phase transformation to BCC at higher temperatures (600 °C to 900 °C). Microstructural characterization demonstrated that cold rolling introduced a high density of dislocations, while annealing facilitated recrystallization and grain growth. The tensile tests indicated that HEA samples exhibited a yield strength of 570 MPa and ductility of ∼36 % with large grain size after a long annealing at elevated temperature. In contrast, after being heat-treated at 1200 °C for 2 min, HEAs restrict FCC-to-BCC phase transformation and exhibit small grain size (3.2 µm) with M23C6-like carbide precipitation in the FCC matrix. Smaller grains provide additional boundaries, which restrict dislocations to bypass these boundaries. While carbide precipitates at grain boundaries and inside grains, it strengthens the material by pinning grain boundaries and restricting dislocation movement, resulting in a yield strength of 610 MPa and ductility of ∼41 %.

Effect of fast multiple rotation rolling on friction surfaced Al[sbnd]Si[sbnd]Cu alloy

In this study, the impact of four linear speeds (75, 95, 115, and 135 mm/min) during fast-multiple rotation rolling (FMRR) on the A390 coating applied via friction surfacing (FS) on the AA1050 substrate was investigated. The microstructure, mechanical properties, and wear resistance were examined using optical microscopy, scanning electron microscopy, electron backscatter diffraction (EBSD), transmission electron microscopy (TEM), nanoindentation tests, microhardness tests, and pin-on-disc tests. Results showed that as the linear speed increased to 135 mm/min, the FMRR-treated layer became 48.6 % thinner. At a linear speed of 135 mm/min, the grain size reduced to 1.24 ± 0.15 μm, and the sizes of Al2Cu and Si particles decreased to 0.51 ± 0.02 μm and 3.45 ± 0.11 μm, respectively. The nano-hardness and Young's modulus increased to 9.11 GPa and 218.9 GPa, respectively. Moreover, the wear rate decreased by 43.53 % compared to the consumable rod and by 65.96 % compared to the AA1050 substrate at a linear speed of 135 mm/min. EBSD results indicated the presence of recrystallization and shear texture components in the FMRR-treated layer. TEM analysis confirmed the presence of nanometer-sized Si particles (<10 nm) and grains (100–500 nm) in the FMRR-processed layer.

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%.

Mineralization of sulfide mound at Wocan-1 hydrothermal field based on geological mapping, mineralogy and sulfur isotope studies, Carlsberg Ridge, Northwest Indian Ocean

The Wocan-1 hydrothermal field is distinct on the occurrence of an active sulfide mound, discovered on an axial volcanic ridge of the slow-spreading Carlsberg Ridge. The size of the mound is comparable to TAG active mound located in off-axis of Mid-Atlantic Ridge. In order to understand its formation and controlling factors, we did field geological mapping, mineralogical and geochemical analysis on the hydrothermal precipitates. Our results show the sulfide mound is ∼ 260 m in diameter and ∼ 50 m in height. The southern area of the mound is enriched in high-temperature Cu-rich sulfides, while the northern area is characterized by moderate-temperature Fe-rich sulfides and a talus of pyrite-anhydrite breccias and sands extending for > 200 m. The pyrite here exhibits recrystallization textures characterized by heavier δ34S compositions when compared to that in the southern area. It is considered that the normal faults extending into the northern area of the mound and the associated mass wasting facilitated the infiltration of seawater, which is responsible for the regional difference in mineralization of the mound. This study contributes to the understanding of the formation and controls of large sulfide mounds on the AVRs at the slow-spreading ridges.

Influence of annealing on the interfacial structure, recrystallization behaviour, and texture evolution of hot extruded Mg/Al laminated composites

The hot extrusion process is ideal for Mg/Al laminated materials; however, there is limited research on annealing for hot extruded Mg/Al laminated composites. In this study, Mg/Al composite tubes were prepared using the direct extrusion-shear deformation (DESD) process. The morphology of the Mg/Al interface at different annealing temperatures was investigated using scanning electron microscopy (SEM). As the annealing temperature increases, the bonding layer thickens, and the number of intermetallic compounds (IMCs) increases. Most of the IMCs tend to grow in a columnar manner perpendicular to the interface bonding layer. The β-Al3Mg2 layer is notably thicker than the γ-Al12Mg17 layer, attributable to the lower diffusion activation energy of β-Al3Mg2. The microstructure and texture evolution of the interfacial region were analyzed using backscattered electron diffraction (EBSD). The results show that the local average misorientation (LAM) within the Al layer is higher than that within the Mg layer, suggesting that the Al layer undergoes more significant plastic deformation and accumulates more strain energy than the Mg layer. The static recrystallization (SRX) fraction of the Mg layer is higher than that of the Al layer. However, The SRX proportion of Mg decreases with increasing annealing temperature due to secondary recrystallization. The annealing temperature significantly affects the grain orientation. As the annealing temperature increases, the deformation texture (S, Brass) of the Al layer gradually transitions to the recrystallization texture (Cube) and finally forms {123}<102> texture.

The influence of hydrogen on the recrystallization texture of a face centered cubic metal

The evolution of an alloy's microstructure in a hydrogen atmosphere at high temperatures is one of the important factors contributing to the degradation in the alloy's strength. The present study aimed to clarify the influence of hydrogen on the recrystallization texture of a face centered cubic (FCC) metal. As a model of FCC metal, commercially pure nickel (Ni) was cold-rolled and then annealed separately in vacuum and hydrogen atmospheres. Subsequently, the recrystallization textures were analyzed using EBSD and XRD. Hydrogen promoted the recrystallization of 〈001〉 − oriented deformed grains while hindering the recrystallization of 〈101〉 − oriented deformed grains. It increased the content of {011} 〈1−11〉 texture, promoted the decrease of R-Cube texture content, hindered the increase of Cube texture content， and hindered the reduction in contents of Brass, Copper, Goss, and S textures. In addition, it had an insignificant effect on {011}〈011〉 texture contents. Hydrogen demonstrated an anisotropic effect on the dislocation movement and density of grains with different orientations. Specifically, it impeded the dislocation movement within <101> − oriented deformed grains while facilitating the dislocation movement within <001> − oriented deformed grains. As a result, hydrogen induced an increase in dislocation density in <101> − oriented grains and a decrease in dislocation density in <001> − oriented grains.

Evolution and mechanism of recrystallization microstructure and texture in GH3536 superalloy foil and their influence on strength performance

To achieve isotropic strength in GH3536 foil, this study investigated the influence mechanism of initial recrystallization microstructure and texture characteristics of GH3536 superalloy foil with different cold-rolled reduction rates (referring to the reduction rate in thickness) on annealing recrystallization microstructure, including secondary recrystallization microstructure, and texture. This was studied by controlling the cold-rolled reduction rate and annealing temperature, in conjunction with microstructure and texture analysis. Meanwhile, this study clarified the dependency of strength performance on recrystallization microstructure and texture. The results of this study indicate that the Coincidence Site Lattice (CSL) grain boundaries and High Energy (HE) grain boundaries did not show significant superiorities, and were not the primary reasons for the formation of Brass ({011}<211>) and Goss ({011}<100>) textures, as well as secondary recrystallization. Instead, by controlling the cold-rolled reduction rate, the initial recrystallization stage formed a significant quantity and size superiority of α-fiber texture ({110}∥ND) in each grain size range. This led to preferential growth, and even abnormal growth of Brass and Goss grains in subsequent high-temperature annealing processes. The control of the α-deformation fiber texture was identified as the driving factor behind the formation of the initial recrystallization texture due to the cold rolling reduction rate. Cold-rolled processes with a deformation amount greater than 40 % yielded a quantity superiority of α-fiber texture shear bands and an appropriate stored energy advantage. This facilitated the nucleation and effective growth of more α grains, while suppressing the random growth of grains with γ-fiber texture ({111}∥ND). Ultimately, a quantity and size superiority was achieved in the initial recrystallization stage. The tensile strength of GH3536 foil was controlled by grain size and texture. By controlling the deformation amount to approximately 30 %, GH3536 foil was successfully produced with no pronounced orientation texture and isotropic strength.

Machine Learning-Aided Analysis of the Rolling and Recrystallization Textures of Pure Iron with Different Cold Reduction Ratios and Cold-Rolling Directions.

We performed a machine learning-aided analysis of the rolling and recrystallization textures in pure iron with different cold reduction ratios and cold-rolling directions. Five types of specimens with different cold reduction ratios and cold-rolling directions were prepared. The effect of two-way cold-rolling on the rolling texture was small at cold reduction ratios different from 60%. The cold reduction ratio in each stage hardly affected the texture evolution during cold-rolling and subsequent short-term annealing. In the case of long-term annealing, although abnormal grain growth occurred, the crystal orientation of the grains varied. Moreover, the direction of cold-rolling in each stage also hardly affected the texture evolution during cold-rolling and subsequent short-term annealing. During long-term annealing, sheets with the same cold-rolling direction in the as-received state and in the first stage showed the texture evolution of conventional one-way cold-rolled pure iron. Additionally, we conducted a machine learning-aided analysis of rolling and recrystallization textures. Using cold-rolling and annealing conditions as the input data and the degree of Goss orientation development as the output data, we constructed high-accuracy regression models using artificial neural networks and XGBoost. We also revealed that the annealing temperature is the dominant factor in the nucleation of Goss grains.

Effect of strain path and short-term post-annealing on the microstructure, texture, and mechanical anisotropy of low-carbon steel

In this research, the effect of strain path and short-term post-annealing on the microstructure, texture, and mechanical anisotropy of low-carbon steel was investigated. Asymmetric unidirectional rolling (AUR) and asymmetric cross rolling (ACR) were applied on Fe-0.072C steel. The ACR-processed sheet revealed a very limited number of new grains compared to the AUR-processed sheet, which was due to the dynamic recovery induced by strain path change. The average ferrite grain size of the post-annealed AUR- and ACR-processed samples was 11.5 and 14.1 μm, respectively. The dominant recrystallization in the annealed AUR-processed sheet was discontinuous static recrystallization, while that in the annealed ACR-processed sheet was continuous static recrystallization. The weak typical rolling textures (γ-fiber and α-fiber) at the midthickness of both rolled sheets demonstrated that the shear deformation effectively contributed to the formation of the shear textures during asymmetric cold rolling. The ACR decreased the intensity of the overall texture more than the AUR process due to the changes in the reference frame of deformation after each pass, which destabilized ideal texture components. The results showed that Goss and {111}〈112〉 components were continuous and discontinuous static recrystallization textures in the asymmetrically cold-rolled low-carbon steel sheet during the annealing treatment, respectively. The annealed AUR-processed sheet revealed a weaker texture as compared to the annealed ACR-processed sheet. The significant changes in the preferred orientations of the annealed AUR-processed sample led to weaker texture intensity compared to the annealed ACR-processed sheet. The hardness of the annealed AUR-processed sheet (183.8 HV) was higher than that of the annealed ACR-processed steel (156.9 HV), which was owing to the larger grain size and also the elimination of the γ-fiber texture in the annealed ACR-processed sheet. The strength along the rolling direction was lower than that along the transverse direction in the AUR-processed sheet. However, in the ACR-processed sheet, the values of strength were similar along three different tensile directions. As an important conclusion, if both high-strength and low-anisotropy are needed in the low-carbon steel sheets, it's better to apply ACR rather than AUR. In addition, if both high toughness and low anisotropy are essential, it's better to use AUR followed by post-annealing rather than ACR + post-annealing. The length of the intermediate stage of work hardening in the annealed ACR-processed sample was much less than the annealed AUR-processed sheet due to the presence of harder orientations (〈111〉 and 〈110〉) along rolling and transverse directions in the annealed ACR-processed sample. Finally, the fracture behavior of deformed and post-annealed steel sheets for both strain paths was ductile and shear ductile.

Effect of Intermediate Annealing on Microstructure and Cold Rolling Hardness of AlFeMn Alloy

The microstructure and texture of an AlFeMn alloy were studied under different intermediate annealing processes, and the changes in microhardness during cold rolling were analyzed. After annealing at 420 °C with a slow heating rate, the alloy showed a high number of small dispersed particles and recrystallization textures dominated by R texture, with deformation textures of 23.5%. Annealing at 610 °C with a rapid heating rate resulted in a significant decrease in the number of small-sized particles and an increase in recrystallization texture contents, with CubeND being the majority. The deformation texture contents decreased to 14.9%. The electrical conductivity of the 420 °C annealed sheet was higher than before annealing, whereas the sheet annealed at 610 °C showed a decrease in electrical conductivity after annealing. This indicated that annealing at 610 °C led to a higher degree of recrystallization and the development of Cube/CubeND due to the dissolution of dispersed particles. During the subsequent cold rolling process, the microhardness of both annealed sheets initially increased and then decreased. However, the microhardness of the 420 °C annealed sheet with varying cold rolling reductions consistently remained lower than that of the 610 °C annealed sheet, as was the cold rolling reduction corresponding to the peak microhardness. The results showed that the precipitation at 420 °C facilitated work softening, while the dissolution at 610 °C promoted work hardening.

Effects of annealing time on microstructural characteristics and mechanical properties of cryo-rolled CoCrFeMnNi high entropy alloys

High-entropy CoCrFeMnNi alloy was subjected to cryo-rolling with a reduction ratio of 25 % and was then annealed at 1050 °C for 5, 25, and 45 min. The results of the recrystallization textures of the various annealed samples showed the presence of similar texture components, indicating that cryo-rolling had only a limited effect on the formation of the subsequent annealing texture. The volume fractions of the different texture components similarly showed no obvious dependence on the annealing temperature. The uniformity of the recrystallization texture suggests the absence of strong preferential nucleation and growth during annealing. The cryo-rolled samples processed with different holding times exhibited a remarkable ambient temperature strength-ductility combination.

Timing of multiple fluid pulses recorded by garnet and accessory minerals in metarodingites

Metarodingites are commonly garnet-bearing metasomatized mafic dykes within serpentinized mantle rocks. Garnet in metarodingites has the potential to preserve compositional and chronological information about the entire metamorphic-metasomatic evolution, from ocean floor formation to deep subduction. In this study, we investigate the chemical and chronological record of garnet, titanite, and zircon from metarodingites and garnet veins in chloritized blackwall, from the Zermatt-Saas zone in the Western European Alps. Garnet in the chlorite-rich metasomatic rind (blackwall) displays re-crystallization and new growth textures and therefore represents a second generation of garnet (Grt2), after the one in the metarodingite core (Grt1). Major and trace element mapping shows that Grt2 is richer in andradite and Ti-andradite components compared to the more grossular-rich Grt1 in the metarodingite. Moreover, we found that in both Grt1 and Grt2, Ti and U content are positively correlated, with U abundances up to 1.5 μg⋅g−1. Grt2 does not show rare earth element (REE) zonation, suggesting that REE transport was facilitaed by the presence of a fluid phase. We propose that the metasomatizing fluids from which Grt2 precipitated, were serpentinite-derived high-temperature brines capable of transporting Fe3+, Ti and REE.LA-ICPMS U–Pb dating of metarodingite garnet Grt1 samples yielded overlapping ages between 43.6 ± 0.9 and 44.1 ± 1.3 Ma, which are consistent with previous estimates of peak metamorphic conditions. Our data indicate that the metarodingite Grt1 grew within <2 Myr, suggesting a rapid burial rate of the unit or fast and pulsed garnet growth aided by the presence of fluids in the intergranular medium. Titanite from the blackwall sample yields an age of 45.0 ± 1.7 Ma and zircon rim an age of 48.0 ± 1.1 Ma, indicating that fluid release and chloritization occurred at peak conditions. U–Pb ages of garnet in the blackwall samples (Grt2) are significantly younger, yielding ages of 40.1 ± 0.9 Ma and 38.4 ± 0.8 Ma, respectively. The presence of multiple generations of metasomatic garnet in the blackwall suggests that periods of increased rock permeability occurred repeatedly, plausibily aided by deformation, as supported by the consistency of our multi-mineral geochronology. We show how garnet from metarodingites and blackwalls records the metamorphic-metasomatic history and can be used to obtain information on (de)hydration reactions and fluid flow during subduction.

Optimizing recrystallization behavior induced by Mn micro-alloying for reduced anisotropy in rolled Al–Cu–Li alloys

The application of rolled Al–Cu–Li alloy is significantly limited by its anisotropy of mechanical properties, which is dominated by microstructures including grain morphology and textures. In this work, the Mn micro-alloying effect with different additions of 0∼0.8 wt% on recrystallization behavior, microstructural evolution, and mechanical anisotropy in rolled Al–Cu–Li alloys is investigated. The results reveal that Mn-free alloy exhibit a high volume fraction (53.4 %) of the deformation textures, including Brass ({110}<1 1‾ 2>), S ({123}<634‾ >), and Copper ({112}<111‾ >), resulting in a large anisotropy in mechanical property. With the addition of Mn, the number density of Al–Cu–Mn precipitates is increased in the as-rolled alloy, which promotes the recrystallization tendencies during solution treatment and decreases the anisotropy. Among the experimental alloys, the 0.4 wt% Mn-containing sample exhibits a large fraction (55.6 %) of grains with no preferred orientation and a evident recrystallization textures including Cube ({100}<001>) and Goss ({110}<001>). This contributes to good comprehensive mechanical properties (YS = 551 MPa, UTS = 583 MPa, EL = 12.0 %) with a much lower anisotropy. However, an excessive addition of 0.8 wt% Mn leads to the grain coarsening and deteriorative mechanical properties. Based on the above results, the relationship between the texture and anisotropy is established using the effective Schmid factor and the equivalent slip system number.

Microstructure evolution and mechanical properties of Mg94Sn3Al2Zn1 alloy under different extrusion processes

Mg alloys offer potential value in the research and application of structural materials, optimizing superior extrusion processes for this purpose has been a major emphasis. This study examined the impact of five extrusion processes (two conventional forward extrusion and three innovative ES techniques) on the microstructure evolution and mechanical properties of Mg94Sn3Al2Zn1 (wt.%) alloys. Findings show that the ES technique dramatically improved the plasticity of the alloy whereas retaining its high strength. Among all the ES samples, the ES-105 sample exhibited the best tensile properties at room temperature. Mechanical properties differ significantly based on microstructure evolution, with CDRX and DDRX being the primary mechanisms for microstructure evolution in Mg94Sn3Al2Zn1 alloys. Compared to the FE samples, the ES samples are distributed with finer and more homogeneous DRXed grains, and the texture components obviously modify, distinguishing from the basal texture in the FE samples, which exhibit recrystallization texture after extrusion. The as-extruded alloy contains mainly Mg2Sn and a small amount of Mg17Al12 as well as denser and finer second phases in the ES samples. These second phases are crucial in weakening the texture by facilitating the recrystallization process via PSN mechanism, thereby inhibiting the growth of the DRXed grains.

Microstructural, texture, and crystallographic analysis of SiC particle incorporation in double-sided friction stir welding of dissimilar aluminium alloys

This paper investigates the impact of incorporating SiC nanoparticles into the welded interface joint of dissimilar aluminium alloys 2024 and 7075. Double-sided friction stir welding (DS-FSW) was performed to investigate the impact of added nanoparticles on the joint's mechanical properties and crack growth rate. Microstructural analysis of the fractured surface was conducted to assess the influence of nanoparticles on crack propagation, while field emission scanning electron microscopy (FESEM) was utilized to examine the grain size distribution across different weld zones. On analyzing the DS-FSW joint with SiC-reinforced particles using electron backscattered diffraction (EBSD), predominant shear texture components such as B/B̅ and C are observed. Additionally, there are deformed textures like Rotating cube (H) {001} <110> and F {111} <112>, along with recrystallization texture elements such as Goss {110} <001>, P {011} <112>, and Cube {001} <101>. Mechanical properties, determined through hardness and tensile tests, were compared between nanocomposite weldments and base metal to assess the improvement in mechanical properties following the inclusion of SiC particles. Crack growth tests were performed using compact test (CT) specimens at a maximum load of 5 kN and a stress ratio of R = 0.1. The addition of SiC nanoparticles to the joint area led to a significant decrease in grain size and an increase in hardness within the stir zone, compared to the base metal and samples without the powder. The tests revealed an approximately 62 % increase in tensile strength and a notable increase in microhardness of the weld zone of the aluminium alloy metal matrix composite (AAMMCs).

Microtextural evidence for the recrystallization of opal-A to quartz in epithermal veins: A case study from the McLaughlin deposit, California

High-grade ores in low-sulfidation epithermal deposits commonly consist of banded veins containing quartz as the most abundant gangue mineral. Previous studies suggested that at least some of the quartz has formed as a product of recrystallization from a noncrystalline silica precursor. Detailed petrographic studies confirm that high-grade veins from the <2.2 Ma McLaughlin deposit in California were originally entirely composed of opal-AG. The noncrystalline silica is isotropic in crossed-polarized light and consists of compacted microspheres that are up to several micrometers in size. In many bands of the high-grade veins, the thermodynamically unstable opal-AG has matured to quartz. The recrystallization of the noncrystalline silica resulted in the development of quartz and ore textures that mask the original conditions of vein formation. Incipient recrystallization of the opal-AG caused the formation of lepispheres consisting of opal-CT as well as the development of concentrically banded silica spheres. Continued maturation led to the growth of elongated quartz crystals or complexly shaped quartz aggregates in the cores of the concentrically banded silica spheres. Amalgamation of quartz crystals caused the development of mosaic quartz or flamboyant quartz. Ripening produced large prismatic quartz crystals, which are characterized by zones of feathery appearance. Fluid inclusions within the quartz formed through recrystallization are typically highly irregular in shape and show inconsistent liquid-to-vapor volumetric proportions, but assemblages with consistent ratios are also present. Bands rich in fluid inclusions occurring along former recrystallization fronts in prismatic quartz crystals resemble growth zones in zonal quartz. Recrystallization of the silica matrix resulted in grain coarsening of the ore minerals and encapsulation of ore minerals by quartz. In areas where recrystallization of the noncrystalline silica proceeded to completeness, the quartz textures could be easily misinterpreted to indicate that quartz growth occurred in open space with the ore minerals infilling vug spaces. Correct recognition of recrystallization textures has significant implications for paragenetic investigations on vein material from epithermal deposits as well as the design of fluid inclusion studies.

Effects of Zr and Hf on superelasticity, shape memory effect and microstructure of β-type (Ti–Zr–Hf)–Nb–Sn multi-principal element alloys with low magnetic susceptibility

(Ti–Zr–Hf)(97−x)–xNb–3Sn (Ti:(Zr + Hf) = 1:1) alloys were designed for biomedical superelastic alloys with magnetic resonance imaging (MRI) compatibility. The effects of Zr and Hf on constituent phases, superelasticity, shape memory effect and magnetic susceptibility were clarified. The specific Nb content for superelasticity and shape memory effect was also explored. It was found that the (Ti–Zr)–6.5Nb–3Sn alloy exhibited a superelastic recovery strain of 5.2 % with lower magnetic susceptibility compared to conventional Ti–Ni and Ti–Nb alloys. The magnetic susceptibility decreased with increasing Hf content. The (Ti–Hf)–9Nb–3Sn alloy showed a superelastic recovery strain of 0.9 % and very low magnetic susceptibility less than half of that of the conventional alloys. Based on the lattice parameters of these alloys, it was found that these alloys exhibited larger transformation lattice strain between a β phase and an α” phase than those of the Ti–Nb alloys, suggesting high potential to exhibit a large superelastic recovery strain. According to orientation analyses of constituting grains, the larger superelastic recovery strain in the (Ti–Zr)–6.5Nb–3Sn alloy than that of the (Ti–Hf)–9Nb–3Sn alloy is considered to be caused by a strong recrystallization texture of {001}β <110>β. By optimization of heat-treatment temperature, superelastic recovery strain of 3.6 % was achieved in the (Ti–0.5Zr–0.5Hf)–7.5Nb–3Sn alloy.

Development of a novel processing technique for cold-rolled Al-3 Mg aluminum alloys via athermally-enhanced electrical annealing

In this study, we proposed an alternative to the conventional warm forming processing for the softening of hard cold-rolled Al-3 wt% Mg aluminum alloys to improve formability. A novel processing technique was proposed via athermally-enhanced electrical annealing. The softening of the aluminum alloy to a maximum 48.2 % micro-hardness decrement at 158.5 °C was achieved via current-induced recrystallization at 4.0 × 104 A/cm2 and above for 1 h, as evidenced by the formation of strain-free equiaxial grains, the release of accumulated residual stress, the transformation of subboundaries and low-angle grain boundaries to high-angle grain boundaries, and the transformation of deformation texture to recrystallization texture. This study aims to provide a sustainable processing technique for the circular economy to achieve lower annealing temperature and energy consumption.