This study investigates the effects of annealing temperature on the recrystallization behavior, microstructural evolution, and mechanical properties of Ti-6Al-4V alloy subjected to 90 % large-reduction warm rolling. Progressive spheroidization and grain coarsening were observed with increasing annealing temperature. At 650 degrees C, the microstructure retained elongated alpha and (3 phases with minimal spheroidization, resulting in the highest ultimate tensile strength of 1286 MPa but poor ductility. At 700 degrees C, the alpha phase was partially spheroidized, achieving a moderate spheroidization fraction with fine equiaxed (3 grains uniformly distributed in the alpha matrix. This condition yielded the optimal combination of strength (tensile strength 1197 MPa, yield strength 1089 MPa) and ductility (elongation 13.2 %). In contrast, annealing at 750 degrees C caused significant grain coarsening, reducing strength but improving elongation. The growth of (3 occurs with the proceeding of alpha spheroidization, accompanied with the redistribution of V. The superior performance under the 700 degrees C condition is attributed to a bimodal microstructure comprising ultrafine spheroidized grains and partially deformed grains, which synergistically enhance dislocation strengthening and deformation resistance, ensuring a balance between strength and ductility.

AZ91 magnesium alloy is a promising lightweight structural material for aerospace and automotive applications, but its poor room-temperature plasticity, rolling-induced cracking, inhomogeneous microstructure, and significant mechanical anisotropy limit its widespread use. In this work, an integrated on-line heating-rolling process was employed to fabricate high-performance AZ91 sheets. By tailoring the initial microstructure via on-line homogenization before rolling, the effects of processing parameters on microstructure evolution, texture development, and mechanical properties were systematically investigated. Results show that static recrystallization is effectively triggered during on-line homogenization. With increasing homogenization time, the {0001}//ND basal texture gradually weakens, and the coarsening of the β-Mg17Al12 phase is significantly suppressed. The sample homogenized for 100 s exhibits full recrystallization and the finest grain size (1.61 μm) after rolling, while the 200 s sample achieves the lowest texture intensity (9.54). Owing to grain refinement and precipitation strengthening, the 100 s homogenized sheet achieves optimal strength-ductility synergy along the rolling direction, with a tensile strength of 407.1 MPa, yield strength of 327.9 MPa, and elongation of 6.0%. This study provides an experimental and theoretical basis for the short-process fabrication of high-performance high-aluminum magnesium alloy sheets.

This study systematically investigates how conventional unidirectional rolling (UR) and cross-rolling (CR) routes influence the microstructure and mechanical properties of AZ91 magnesium alloy, providing crucial insights for developing high-performance, near-isotropic magnesium alloy sheets. The microstructure of the magnesium alloy was examined using techniques such as scanning electron microscopy, electron backscatter diffraction, and transmission electron microscopy. The investigation demonstrated that the initial CR pass produced sheets featuring multi-directional slip bands and a bimodal texture, which provided nucleation sites for discontinuous dynamic recrystallization (DDRX) during subsequent deformation. The second CR stage produces a fine-grained microstructure with an average grain size of 1.76 mu m, featuring uniformly distributed nanoscale precipitates and a recrystallization fraction of 73.4 %. DDRX significantly weakens the basal {0001}//ND texture to a minimum intensity of 10.95, enabling the development of near-isotropic mechanical properties. The optimal RTR processing route (RD-*TD-*RD) achieves an exceptional strength-ductility synergy, with tensile strength reaching 371.6 MPa (RD) and 368.0 MPa (TD), yield strength of 310.6 MPa (RD) and 304.3 MPa (TD), and elongation of 7.9 % (RD) and 8.2 % (TD). This enhancement stems from the synergistic effects of grain refinement, precipitation strengthening, and texture randomization mediated through DDRX activation at multi-directional slip bands. Notably, the optimized RTR process achieves this balanced performance using conventional rolling equipment without requiring complex procedures, demonstrating strong potential for industrial applications where consistent multi-directional properties are essential.

Cu-Fe alloys exhibit excellent performance, and increasing Fe content reduces costs. However, high-Fe Cu-Fe alloys exhibit limited formability at room temperature, while warm rolling improves their processability. This research investigates the effect of rolling temperature on the microstructural transformations and texture development in the Cu-10Fe alloys. The experimental result is that during cold rolling, the morphology of Fe phases is mainly fibrous. With the rolling temperature rising, the microstructural morphology of Fe phases becomes globular / elliptical. The difference is that with the increase in rolling temperature, the average grain size of the Cu-10Fe alloy first decreases and then increases. The matrix microstructure remains dominated by deformed grains, with significant recovery observed at 500 °C. The Fe-phase microstructure primarily consists of substructured grains, and dynamic recovery intensifies with rising temperature. During cold rolling, high dislocation density and localized strain heterogeneity lead to dispersed texture orientations and low strength. In contrast, warm rolling promotes dislocation climb and dynamic recovery, triggering partial recrystallization. This reduces randomly oriented grains, enhances the strength and continuity of specific textures, and establishes a more concentrated texture distribution. This forms a structure with fine recrystallized grains embedded within deformed grains, exhibiting slightly lower strength than cold-rolled samples but better elongation. These findings reveal the crucial role of deformation temperature in controlling microstructure transformation and texture evolution, especially by regulating the recovery and recrystallization behaviors of Cu-10Fe alloys. The above results hope to provide some theoretical and experimental basis for a new approach to improve processing technologies for new Cu-Fe-based composites.

Cu–Fe alloys combine the high electrical conductivity of Cu with the strengthening and magnetic contributions of Fe, making them promising high-strength, electrically conductive functional materials. However, for high-Fe Cu–Fe alloys with Fe contents exceeding 10 wt.%, the microstructural response, texture evolution, and two-phase deformation partitioning during warm rolling remain insufficiently understood. In this study, Cu–10Fe, Cu–15Fe, and Cu–20Fe alloys were investigated to clarify the effect of Fe content on microstructure evolution, texture characteristics, deformation behavior, and property balance after single-pass warm rolling at 500 °C with a 50% reduction. The results show that, as the Fe content increased from 10% to 20%, the Fe-rich phase became progressively denser after warm rolling and gradually transformed from discrete spherical/spindle-like particles into fibrous structures distributed along the rolling direction, while the average grain size of the alloy decreased. EBSD analysis indicates that increasing Fe content weakened the preferred orientation of the Cu matrix. The maximum texture intensity of the Cu matrix decreased from 5.08 to 4.21, and texture showed a weakening trend. The mechanical properties show that, with increasing Fe content, the ultimate tensile strength increased from 434 MPa to 514 MPa, whereas the elongation decreased from 10.7% to 5.1%. This indicates that the increased amount of Fe-rich phase enhanced strength but reduced plasticity; nevertheless, dynamic recovery and local recrystallization induced by warm rolling helped maintain a certain degree of ductility. The electrical conductivity decreased from 19.43% IACS to 16.71% IACS with increasing Fe content, corresponding to a decrease of only approximately 2.7% IACS, suggesting that warm rolling partially mitigated the negative effect of increasing Fe content on electrical conductivity. Based on the combined microstructural, texture, and KAM/GND analyses, the deformation behavior of the alloys with increasing Fe content exhibited a transition from heterogeneous deformation dominated by the Cu matrix/interface to cooperative deformation involving the Fe-rich phase.

In this research, Cu-Fe alloys with Fe compositions of 5, 10, 20, and 30 % were successfully fabricated using a novel spray-forming method and followed by cold rolling. The impacts of varying Fe compositions on solidification behavior, microstructure evolution, and mechanical characteristics were systematically investigated using various analytical methods, including OM, EPMA, XRD, SEM, EBSD, and TEM. The findings demonstrate that the Fe particles of the spray-formed Cu-Fe alloys with all components exhibit a fine and uniform distribution within the Cu matrix. With the increase in Fe compositions, the average grain diameter of the Cu matrix is obviously refined. The deformation behavior and the reinforcement mechanisms of Cu-Fe alloys with different Fe compositions during cold rolling were also explored. After cold rolling, Cu grains and Fe grains were distinctly refined and stretched into fibers in the rolling direction. The extent of Fe fibers became more pronounced as the Fe composition. The Cu matrix formed strong copper and brass textures. The strength of the spray-formed Cu-Fe alloy after cold rolling increased as the Fe composition increased. The enhanced strengthening effect of the alloy is predominantly attributable to a synergistic combination of high dislocation density within the Cu matrix, grain refinement, and Fe grain fibrillation. Furthermore, the strengthening mechanism of the spray-forming Cu-Fe alloy after cold rolling aligns with the Hall-Petch relationship. The research lays a solid foundation for the preparation and industrial production of Cu-Fe alloys with high Fe compositions.

This study systematically investigates the influence of rolling temperature (cold rolling to 500 °C) on the microstructure and properties of Cu–10Fe alloy. The results show that with an increasing temperature, the Fe phase morphology transitions gradually from fibrous to spherical/ellipsoidal, while the Cu grain size first decreases and then increases. At 500 °C rolling, a bimodal structure forms (fine recrystallized grains coordinate deformation, and coarse grains provide strengthening), with dynamic recovery significantly reducing dislocation density, but the recrystallization rate remains only 11.9%. Texture analysis reveals that in the cold-rolled state, Brass-R texture (2.45) dominates, resulting in low elongation (1.96%). At 400–450 °C, the synergistic effect of Goss and Copper textures (6.9–13.82) improves elongation to 7.03%. At 500 °C, Brass texture (14.58) becomes dominant, increasing elongation to 9.21%, and tensile strength rises from 443 MPa to 472 MPa. Electrical conductivity increases from 10.09% IACS (cold-rolled) to 19.43% IACS (500 °C), mainly due to dynamic recovery and Fe precipitation alleviating lattice distortion.

With the increasing demand for automotive lightweight leading to greater use of high-strength steel materials, the friction behavior between the sheet and the tool during the forming process has become more complex, significantly affecting the surface quality of stamped parts and tools, the amount of springback, and the uniformity of plastic deformation. To accurately predict the complex friction behavior during the stamping process and effectively evaluate the forming quality and springback precision, this study developed a friction model based on physical friction principles, incorporating key influencing factors such as contact pressure, temperature, and sliding speed. The model utilized laser confocal microscopy measurement and analysis techniques to statistically characterize the height distribution of the contact regions between carbide-free bainitic steel sheets and SKD11 tool surfaces. By combining image processing methods, the indentation depth of tool surface asperities was calculated, and the evolution of microscopic material surface morphology under loading, sliding and bulk strain conditions was investigated to analyze its impact on the friction coefficient. Comparative analysis between experimentally measured friction coefficients and model predictions validated the accuracy and effectiveness of the proposed friction model. Finally, the model was applied in finite element simulation to simulate the U-shaped stretch-bending process under different blank holder forces and sliding speeds. The results demonstrated that, compared to the traditional Coulomb friction model, the proposed model exhibited better agreement with experimental data, providing more accurate predictions of friction behavior during the stamping process.

Three-way servovalve controlled cylinder (TSCC) is the main method used in hydraulic automatic gauge control (HAGC) system of rolling mill, which generally only foucus on the screw-down speed of HAGC cylinder under load resistance. However, with the development of plan view pattern control and variable gauge rolling, the lifting-up speed of HAGC cylinder is required to be as high as the screw-down speed. At present, high frequency response and large flow servovalves or even double servovalves in parallel are usually used to achieve high lifting-up speed, resulting in a substantial increase in equipment cost. In this paper, the nonlinear mathematical models of the TSCC and four-way servovalve controlled cylinder (FSCC) are firstly established, and the steady-state speed equations of the two methods are derived. Then, the steady-state speed of the two methods with different HAGC cylinder sizes under different load conditions is compared and analyzed, and it is proved that FSCC has obvious advantages in lifting-up speed. Finally, simulation experiments of variable gauge rolling on a 1 050 mm cold-rolling mill are carried out. In the rolling process of transition zone where the roll gap increases, the FSCC has higher control precision and wider dynamic adjustment ability, which is more conducive to improving rolling speed, production efficiency and shape quality.

The manufacturing process for wrought Ti alloys with the hexagonal close-packed (HCP) structure introduces a complicated microstructure with abundant intra- and inter-grain boundaries, which greatly influence performance. In the hexagonal close-packed (HCP) structure, two types of grain boundaries are commonly observed between grains with ~90° misorientation: the basal/prismatic boundary (BPB) and the coherent twin boundary (CTB). The mechanical response of the BPB and CTB under external loading was studied through molecular dynamic simulations of HCP-Ti. The results revealed that CTB undergoes transformation into BPB through the accumulation of twin boundary (TB) steps and subsequent emission of Shockley partial dislocations. When the total mismatch vector is close to the Burgers vector of a Shockley partial dislocation, BPB emits partial dislocations and further grows along the stacking faults. When a pair of CTBs are close to each other, severe boundary distortion occurs, facilitating the emission and absorption of partial dislocations, which further assists the CTB-BPB transformation. The present results thus help to explain the frequent observation of coexisting CTB and BPB in HCP alloys and further contribute to the understanding of their microstructure and property regulation.

In this study, the austenite formation behavior is investigated for the ferrite–pearlite initial microstructure, considering the influence of ferrite recrystallization and cementite distribution. Special attention is also given to the effect of recrystallization state on cementite distribution for varied heating routes. Austenite nucleation for varied recrystallization state is elucidated in terms of activation energy evaluation and post microstructural characterization, and the austenite transformation kinetics are modeled and experimentally validated. In the uncrystallized state, austenite forms on the original pearlite colonies quickly due to the short carbon diffusion path. The high activation energy leads to the exceptionally difficult nucleation at the ferrite–cementite interface inside ferrite matrix. Once recrystallization occurs partially, priority of austenite nucleation is on those ferrite boundaries (both recrystallized and unrecrystallized boundaries) decorated by cementite. With complete recrystallization, preferential nucleation sites are found to be junctions of ferrite–cementite interface on recrystallized ferrite boundaries. Austenite transformation kinetics is well predicted by considering the varied nucleation density due to different recrystallization state, showing a good agreement with experimental data. It is demonstrated directly by experimental evidence that proceeding of recrystallization postpones the austenite transformation kinetics, while getting rid of the interference of heating rate and nucleation location.

In this paper, the solidification microstructure characteristics of metastable immiscible Cu20Fe alloys under natural cooling conditions and subsequent cold rolling were analysed. The findings demonstrate that the Cu20Fe alloy underwent a liquid–solid transformation under natural cooling conditions. The equiaxed Cu matrix and the Fe dendrites exhibited elongation into ribbon-like structures parallel to the cold rolling direction. Following cold rolling, the mean grain size of the Cu20Fe alloy was considerably refined, and the mechanical properties were improved. After cold rolling, the Cu matrix formed both {112}<111> copper and {110}<112> brass textures. Furthermore, the strengthening mechanisms of the cold-rolled Cu20Fe alloy are primarily dependent on the strengthening of grain boundaries and work hardening. This provides an economically friendly method for the preparation of Cu-Fe alloys with high Fe compositions.

To prevent or reduce the issue of macroscopic segregation in metastable immiscible Cu-Fe alloys during solidification, the alloys were produced using spray forming technology and subsequently cold rolled. The Cu10Fe alloy microstructure characteristics were investigated, and its mechanical properties were evaluated and compared with those of cast alloys. The results show that the alloy produced by spray formed has a well-dispersed Fe phase and the grain size is smaller, which effectively suppresses macroscopic segregation. The mechanical properties of spray-formed Cu-Fe alloys are higher than those of cast alloys, and the tensile strength and elongation of the alloys after cold rolling are 584 MPa and 2.2% respectively. The study provides valuable insights into the optimization of spray deposition techniques for producing high quality Cu-Fe alloys.

In order to solve or suppress the problem of macro segregation of Fe phase of Cu-Fe alloy in the traditional casting process, we successfully prepared Cu-10Fe alloy prefabricated slabs with homogeneous and fine microstructure by spray deposition and achieved high strength Cu-10Fe alloy thin strips by subsequent cryorolling. Cryorolling was carried out at different reductions to investigate the relationship between microstructure evolution and mechanical properties. The results show that the spray deposited alloys have good plasticity and low temperature workability. As the reduction increased, the Fe phase becomes more fibrous and the average grain size of the alloy is refined to 0.35 μm. The {112}<111> texture was gradually transformed into a stabilized {110}<112> texture during cryorolling suggested that the low temperature suppressed cross-slip and improved the strength of the alloy. The mechanical properties of the alloys improved significantly after cryorolling is mainly attributed to the significant grain refinement, dislocation accumulation and the presence of ultrafine grains during the cryorolling process. The successful development of thin strips of Cu-Fe alloy with uniform distribution of Fe phase and high strength provides a new idea for the preparation of thin strips of immiscible alloys such as Cu-Fe alloy.

In order to obtain homogeneity and fine-scale microstructure of Cu–Fe alloy, a Cu-10 wt

To address the challenges associated with preparing thin strips of difficult-to-deform materials - such as low processing efficiency and yield, poor shape, and subpar performance our research team developed an on-line warm rolling experimental machine featuring hydraulic tension. We used the Ti-6Al-4V alloy as our experimental material and conducted warm rolling experiments at various temperatures, thoroughly examining the intricate relationship between microstructure evolution and mechanical properties. Our findings indicate that warm rolling causes a clear refinement of the a phase and b phase microstructures, while intensifying dislocation entanglement. These changes significantly enhance the strength of the Ti-6Al-4V alloy, though Total Elongation Limit (TEL) decreases. After evaluating mechanical properties, surface quality, and energy consumption associated with warm rolling, we determined the optimal warm rolling temperature for the Ti-6Al-4V alloy to be 650 degrees C. At this temperature, the Ultimate Tensile Strength (UTS), Yield Strength (YS), and TEL were 1325 MPa, 1164 MPa, and 8.0%, respectively, maintaining good ductility. The impressive performance of the Ti-6Al-4V alloy sheet is mainly attributed to the strengthening effects of fine grain and dislocation, while the introduction of some fine recrystallization enhances ductility. High-performance Ti-6Al-4V alloy thin strip was successfully prepared by on-line warm rolling with hydraulic tension, which provided a new idea for the preparation of thin strip of difficult-to-deform materials. (c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC

Abstract In this study, two AZ91 samples were produced by compression at 200 °C and 350 °C, respectively. The microstructure of the samples and their effect on deformation were studied. The results show that the deformation mechanism is slipping, twinning and shear banding at low temperature due to the low compression temperature. The stacking fault energy of alloy can be increased by the increase of adiabatic temperature, the dislocations gather at the shear band, resulting in the increase of hardness, which is not conducive to deformation. At high temperature, there were a large number of fine second phases precipitated at the shear bands. This second phase provides nucleation site for recrystallization, and dislocation energy storage in the shear band provides energy for recrystallization, resulting in recrystallization nucleation and growth at the shear bands. Discontinuous dynamic recrystallization weakened texture intensity.

As a typical dual-phase titanium alloy, Ti-6Al-4V has a complex phase transformation process, which is sensitive to temperature parameters and difficult to control its microstructure. To further master the law of phase transformation of Ti-6Al-4V titanium alloy and make a reasonable heat treatment system, different heat treatment systems in β single-phase region and (α+β) two-phase region were made for Ti-6Al-4V titanium alloy, and the phase transformation process and microstructure growth rate of different heat treatment processes were studied by high-temperature confocal microscope. At 1050 °C and 1200 °C in the β single-phase region, the β grain size increases with the prolongation of the holding time and the increase of the holding temperature. The tissue growth rate of the α phase was higher than 1200°C in the cooling process after 1050°C incubation, which was 2.88 μm/s. Based on the heat preservation in the single-phase region, the second heat preservation was carried out for the two-phase region of Ti-6Al-4V titanium alloy at 850 °C and 900 °C. The study found that when the holding temperature was 850°C, the fastest growth rate of the α phase was 4.64 μm/s, which was greater than 3.29 μm/s when the holding temperature was 900°C.