Accurate prediction of strain distribution in sheet metal stamping is critical for optimizing formability and ensuring structural integrity in large-scale components. However, traditional Finite Element Analysis (FEA)-based methods often suffer from systematic errors due to simplified boundary conditions, and existing deep learning models generally lack physical interpretability. To address this challenge, a physics-aware computational framework was proposed to reduce the discrepancy between simulation-based predictions and experimental observations. A hybrid Transformer-XGBoost (T-X) correction mechanism was developed to correct discrepancies in FEA-derived strain fields. The model performance was further evaluated through multi-scale characterization of Q345NQR2 weathering steel. The corrected model achieved an average relative error of 3.95

The sluggish aging response of Inconel 625 alloy has long limited its precipitation strengthening potential, restricting its application in high-demand environments. Conventional γ″ precipitation requires hundreds of hours of thermal exposure, making the process highly time-inefficient. To address this challenge, short-time stress aging was employed to accelerate precipitation kinetics and enhance mechanical performance. Stress-free and stress aging treatments were conducted at 650°C for 50-200 h, and the γ″ precipitation behavior was examined using TEM, EBSD, and first-principles calculations. Stress aging promoted rapid γ″ nucleation, producing a high precipitate number density and fine morphology. Compared with 200 h of stress-free aging, stress aging for only 50 h and 150 h increased the yield strength by 105.8 MPa (16.0%) and 175.9 MPa (26.6%), respectively, while maintaining comparable ductility. The refined γ″ precipitates restricted dislocation slip and promoted the activation of low-Schmid-factor slip systems, stacking faults, and deformation twinning, thereby achieving a superior strength-ductility synergy. These results demonstrate that short-time stress aging is a precise and time-efficient strategy for tailoring γ″ precipitation, providing new insights into microstructure design and performance optimization of Ni-based superalloys.

The work is conducted to uncover and simulate the dependence of the evolving anisotropic-asymmetric yield behavior on the temperature for an Mg-Gd-Y alloy. Experiments were carried out at 25∼300 °C, including uniaxial tension and compression. The strength is observed to decrease non-linearly as the temperature increases. Thermal softening effect is not significant when the temperature is lower than 200 °C, but the strength decreases dramatically at high temperature than 250 °C. Tension-compression asymmetry and anisotropy are observed to be strongly and nonlinearly dependent on strain and temperature. The temperature effect is taken into account in a combined Swift-Voce (SVT) model to predict the temperature-dependent strain hardening behavior with a higher accuracy than the traditional Johnson-Cook and Zerilli-Armstrong equations. An analytical Yoon2014 (A-Yoon2014) yield function is established to capture the evolving anisotropic-asymmetric behavior with respect to strain and temperature. The predicted force-stroke curves of the A-Yoon2014+SVT model are closer to the experimental results of the three-point bending process than the numerical results of the original Yoon2014+SVT model. Given its user-friendliness and high accuracy for the modeling of temperature-dependent anisotropic-asymmetric hardening behavior, the A-Yoon2014+SVT model is recommended to be utilized in the numerical simulation of plastic forming process for hexagonal close-packed metals.

The construction and stabilisation of soft-rock tunnels pose significant challenges due to rock's inherent properties, like low strength and high deformability. Traditional passive support systems often fail to effectively control tunnel deformation, leading to increased construction costs and delays. Alternatively, the adoption of prestressed anchor cables as an active support has proven effective in controlling soft-rock tunnel deformation. However, the issue of prestress loss in anchor cables has received scarce attention, hindering the widespread application of this active support system. This study investigates prestress loss in anchor cables and evaluates how their composition design and construction affect anchoring performance in the soft rock Muzhailing tunnel in China. Through comprehensive field and laboratory tests, the research identifies that the original design of prestressed anchor cable system led to a significant prestress loss rate of 30%–55%. To mitigate this, an optimised construction scheme was proposed, adjusting specifications, configurations, and construction techniques according to geological conditions. Implementation of this scheme reduced the prestress loss to 25%–35%. Based on these results, a generalised adaptive construction scheme for using prestressed anchor cables to support soft-rock tunnelling is proposed, aiming to provide some practical guidelines for enhancing soft-rock tunnel structural integrity and construction safety.

Accurately characterizing the evolution characteristic of hardening behavior is helpful for the design of metal forming processes. To depict the direction- and stress state-related evolving characteristic, the study proposes an anisotropic-strength differential (SD) hardening model with the form of the first stress invariant, third deviatoric stress invariant, and non-quadratic Hershy-Hosford function. The material parameters can be analytically determined by four hardening curves under the typical stress states. Through adopting a geometry-inspired numerical convex analysis approach, the limits of the convexity-related parameters are efficiently computed to present the determined convexity domain. The established SD hardening model is employed to explain the deformation history-related hardening behavior of WE43 alloy under various stress states. These predicted results have a high consistency with the actual yield stresses. The proposed yield function shows a higher superiority than the existing model in the aspect of characterizing the low strength under plane strain tension (PST). The SD hardening model is extended to the anisotropic form under non-associated flow rule, where the Hill48 yield function is utilized as the plastic potential function. The predicted results indicate that the established model can accurately capture the anisotropic and SD effects of WE43 alloy. This implies the tremendous potential to model the anisotropic-SD hardening performance with low strength under PST for other materials.

Synchronous extrusion from independent directions for each port is a potential approach for manufacturing multidirectional structural components (MDSCs). However, its universality and flexibility are limited by the need for specific forming devices, and the accuracy constraints of these devices may lead to folding defects and nonuniform microstructures. To address these challenges, this study proposes a synchronous multidirectional extrusion (SMDE) method based on uniaxial load. The uniaxial load is synchronously decomposed and redirected into multiple independent movements by toggle-arm mechanisms. This method allows excellent flexibility in manufacturing MDSCs since almost arbitrary load direction is available by adjusting the angle and size of the toggle-arm. Moreover, the load synchrony will be easier enabled by the rigidity of toolsets rather than the accuracy of the devices. The feasibility of SMDE was demonstrated by manufacturing an MDSC with square ports and orthogonal ribs using 2195 aluminum-lithium alloy. The investigations in material flow and microstructures at different forming stages revealed non-uniform forming mechanisms influenced by the nonlinear kinematic characteristics and multidirectional discrepancies. Results show that the progressive reduction in horizontal velocity, combined with additional compression, reduces inter-directional variations in height of thin-walled ports, improving the dimensional accuracy. Meanwhile, the active control of nonuniform deformation with additional compression promotes uniform dynamic recrystallization and grain refinement, leading to uniform microstructures and near-isotropic properties across the ports. The average yield strength, ultimate tensile strength, and elongation were tested to be 487.4 MPa, 529.4 MPa and 8.2 %, respectively. Moreover, the strength heterogeneity of the tested ports was calculated to below 1.39 %. This work provides theoretical and experimental guidance for optimizing of multidirectional load paths and actively controlling nonuniform deformation, and offers a novel and efficient method for the precision forming of MDSCs with arbitrary orientations.

The activation of extension twin variants in magnesium (Mg) alloys during room temperature deformation normally follows the Schmid Factor (SF) criterion, but it also exhibits anomalous activation driven by stress concentrations from the grain neighbor. This study utilized in-situ EBSD in conjunction with molecular dynamics (MD) simulations to investigate a rolled Mg-Gd-Li-Zn-Al alloy. We investigated twin variant selection, interactions between distinct variant types, and the effect of twinning activity on macroscopic mechanical characteristics during rolling direction (RD) compression at low strain rates. The results indicated that in regions characterized by a uniform stress distribution, twin variant activation followed Schmid's law, with twins preferentially activating the variant with the highest Schmid factor (SF). Conversely, in grains subjected to stress concentrations from nearby grains, twinning exhibited anomalous non-Schmid behavior, which was determined by the minimization of the c-axis displacement gradient tensor component imposed by surrounding grains. During plastic deformation, {10-12} twins formed within grains and grew sequentially or simultaneously. Identical variations tended to grow in parallel and coalesced upon impingement during the thickening stage. In contrast, interactions between conjugate variants increased stress concentrations at their interfaces, causing a shift to either universal or unidirectional thickening. These findings contribute to a better knowledge of twin variant selection, variant interactions, and their effects on the macroscopic mechanical characteristics of magnesium alloys.

Herein, low-Gd-content Mg-Gd-Zr system alloys with novel strength and adequate ductility were prepared by Nd and Y elements alloying combined with hot extrusion. The effects of Nd and Y elements on the microstructure, texture and mechanical properties of as-extruded Mg-6Gd-0.5Zr (VK61), Mg-4Gd-2Nd-0.5Zr (VEK421) and Mg-4Gd-2Y-0.5Zr (VWK421) alloys were investigated. The results showed that the addition of Nd not only refines and homogenizes the alloy structure but also promotes the dynamic precipitation of the secondary-phase particles during the extrusion process; while the addition of Y significantly inhibits the recrystallization behavior of the alloy during extrusion, forming a typical bimodal structure. After extrusion, the VK61 and VEK421 alloys consisted of fine dynamic recrystallization (DRX) grains while the VWK421 alloy consisted of fine DRX grains and coarse deformed grains. The as-extruded VEK421 alloy demonstrated optimal plasticity, characterized by a UTS of 245.4MPa and an EL of 33.6%. The as-extruded VWK421 alloy had the highest volume fraction of the second phase, the lowest recrystallization volume fraction, and the highest texture intensity. It also exhibited optimal tensile strength; ultimate tensile strength (UTS) and elongation (EL) were 261.6MPa and 18.2%, respectively, 66.7% and 106.8% higher than the as-solutionized alloy. The alloy-strengthening mechanisms mainly include fine grain strengthening and dislocation strengthening. Moreover, the presence of DRXed grains with a weak texture plays a significant role in improving the plasticity of the alloy.

Laser powder bed fused Ti2AlNb alloy exhibits excellent strength and ductility at room temperature but suffers from severe brittle fracture at 650 degrees C. To uncover the underlying mechanism, this study systematically investigates the microstructure evolution and mechanical responses at 450 degrees C, 550 degrees C, and 650 degrees C. Results show that the B2 -> O phase transformation occurs above 380 degrees C, with the O phase precipitating as nanoparticles at 450 degrees C, growing into acicular morphology at 550 degrees C, and coarsening dramatically at 650 degrees C. The interface between O and B2 phases induces local stress concentration. At 550 degrees C, deformation twinning is activated, alleviating stress and leading to an anomalous work-hardening effect. However, at 650 degrees C, the overgrown O phase suppresses twinning, resulting in catastrophic brittle fracture. The morphological evolution of the O phase is thus identified as the key factor governing the high-temperature property degradation.

The mechanical properties, isotropy and fracture behavior of Ti-6Al-2Sn-3Mo-1Cr-2Zr-2Nb (TC21) alloy after quasi-beta forging were studied from the competition between the boundary development of beta matrix and dynamic precipitation of alpha lath (alpha L). Two heat treatment routes were performed on the quasi-beta forged alloy: (i) double annealing (DA), including a solution treatment in alpha+beta domain followed by an aging treatment, and (ii) triple annealing (TA), three steps including an extra solution treatment before DA in single beta domain. During the solution treatment in DA, the continuous dynamic recrystallization (cDRX) based on the consumption of residual distortion energy occurred in beta matrix, along with the precipitation of alpha L. It pinned the cDRX of beta matrix in reverse, thus small alpha L and beta sub-grains were obtained, and meanwhile the anisotropy of beta matrix was slightly diminished due to the alpha L pinning. Under tensile strain, these small alpha L caused strong interface strengthening. Meanwhile, they were easier to rotate to accommodate the overall deformation between beta matrix and alpha L, thus increasing the ductility of the material. The TA heat treatment allowed the beta matrix to fully become equiaxial before the alpha L precipitation to eliminate the anisotropy after quasi-beta forging. However, it resulted in the coarsening of beta matrix, with the formation of a continuous and thick boundaries (alpha GB). It caused the formation of precipitate-free zones (PFZs) that became crack origins and propagation paths under tensile strain, deteriorating the ductility of the material. Meanwhile, the larger alpha L precipitated in the fully cDRXed grains. They were more difficult to rotate to accommodate the deformation between beta matrix and alpha L under strain, thus further decreasing the ductility.

In the thixotropic-plastic compound forming (TPCF1) of aluminum alloy and steel, a tough and strong interface is helpful to not only the decrement in the risk of shrinkage crack, but also the metallurgical bonding. In this work, a Ni interlayer was introduced in the TPCF of 7075 Al alloy and 304 L steel. The effects of the Ni interlayer thickness, and a bonding-strengthening diffusion heat treatment before forming on the interface microstructure at two typical strained areas were studied. Moreover, the microstructure and shear strength of the interface after the heat treatment followed by TPCF were further studied, and the relationship between the microstructures and mechanical properties were discussed. Results showed that a Ni interlayer with a thickness of 10.5 μm is helpful to improve the bonding interface by the formation of Ni-Al intermetallic compounds (IMCs2). Most of them are tougher than brittle Fe-Al IMCs obtained as the Ni layer was not introduced, and thus playing key roles in the improvement in interface bonding by releasing the stress concentration near interface. A bonding-strengthening diffusion heat treatment under 750 °C/ 2 h improved the formation of Ni-Al IMCs and contributed to decrease the growth rate of IMCs layer in subsequent heat treatment. The optimal interface shear strength was tested to be 42.4 MPa (a 60

This study combined in-situ EBSD, TEM, HR-DIC with CPFEM simulation to elucidate the micromechanisms governing orientation evolution in a solution-treated Mg-6.3Gd-3.0Li-2.0Zn-0.5Al alloy under tensile deformation. CPFEM simulations showed parallel stress concentration bands within the target grain, suggesting that local stress heterogeneity was closely associated with the activation and evolution of twin variants. An initially hard-oriented grain underwent complete reorientation through competition between twin-variant coalescence and impingement. Identical variants (e.g., V2-V2 and V5-V5) exhibited extremely high geometric compatibility (m ' > 0.999), causing twin boundary elimination and merger into larger uniformly oriented regions; HR-DIC revealed continuous, homogeneous strain distribution, accelerating matrix consumption. In contrast, different variants (e.g., V2-V5 and V2-V4) showed very low geometric compatibility (m '<0.015), forming stable TTBs that generated lattice distortion, slip accumulation, and strain discontinuities, inducing grain subdivision and local hardening. Pole figure analysis confirmed an overall rotation of approximately 86.3 degrees.

Additive manufacturing technology is an effective approach to realize the integral forming of complex components of aluminum matrix composites (AMCs). However, the interfacial reaction between graphene nanoplatelets (GNPs) and the Al matrix is a key issue restricting their reinforcement efficiency. In this study, Cu powder was uniformly coated on the surface of GNPs by a wet mixing process, combined with multi-pass hot drawing plastic deformation, so that the GNPs–Cu powder was uniformly dispersed inside the Al wire. During the wire arc additive manufacturing (WAAM) process, the copper layer can effectively block the direct contact between GNPs and the Al matrix, thereby inhibiting the harmful interfacial reaction. The results show that in the 5 vol pct GNPs/AlCu composite, GNPs are uniformly distributed, and a large number of Al2Cu precipitates are formed around GNPs. There is no Al4C3 brittle phase generated at the interface, and the GNPs–Al interface is clean and intact. Benefiting from the above microstructural characteristics, the tensile strength and yield strength of the composite are increased by 42 and 37 pct compared with pure AlCu alloy, respectively. This work can provide a new idea and method for the additive manufacturing of high-performance AMCs.

Nickel-based superalloy components prepared by laser powder bed fusion (LPBF) are increasingly being used in the hot ends of aeroengines, which still need to be laser-welded to realize the assembly connection of large closed structures. However, the unique microstructural characteristics of LPBFed parts render them more poorly weldable than casts and wroughts, especially in cracking-sensitive superalloys. In this study, cracking mechanisms were analyzed by performing laser deep fusion welding on an LPBFed Haynes 230 alloy. The key factors leading to weld cracking were strongly correlated with the low-melting-point TCP phases enriched with W, Si, Al, and silicides, both of which tended to be distributed in the boron(B)-rich region and exhibited poor coherence with the matrix. In addition, the flow behavior of the molten pool affected the solidification rate of the weld, resulting in large solidification shrinkage stresses in the cracking-sensitive zone (CZ) part of the weld. In order to minimize the development conditions of the cracking-sensitive phases, reducing the content of W (from 14.96 to 13.56 wt.%) and Si (from 0.47 to 0.25 wt.%) was chosen to alleviate the segregation of W, Si and C elements in the solid phase at the end of solidification. Thus, TCP phase and silicides were transformed into carbides, which successfully suppressed weld cracking, reducing the crack depth ratio from 0.70 ± 0.08 to zero. New insights into the weldability improvement and crack inhibition mechanism of laser-welded additively manufactured cracking-sensitive superalloys are provided, accelerating the rapid application of large assemblies.

This study designed novel CoCrNi and CoNiV medium-entropy alloy interlayers for laser welding of titanium-steel dissimilar joints, fundamentally avoiding the corrosion-induced failure common in copper-containing joints under pressurized water reactor conditions. Both joints achieved their maximum strength under identical processing parameters, with the CoNiV interlayer exhibiting a broader parameter window for robust bonding. The two joints exhibited distinct bonding mechanisms: fusion-brazing for the CoCrNi joint and full fusion welding for the CoNiV joint. These mechanisms accounted for the differences in the average thickness and through-thickness uniformity of the reaction layer on the TC4 side, as well as the resulting fracture paths. The reaction layer was composed of two sublayers: a Ti-rich layer and a Ti-depleted layer. In the CoNiV joint, the substitution of V for Cr reduced the hardness and elastic modulus of the constituent phases, improved interfacial phase compatibility, and lowered thermal residual stresses. As a result, the CoNiV joint achieved a tensile strength of 331.98 MPa, representing an increase of 94.5% over the CoCrNi joint. All fractures occurred within the reaction layer on the TC4 side and displayed a brittle fracture mode.

Forging-induced crystallographic texture critically governs the creep anisotropy of near-alpha titanium alloys, directly compromising the reliability of high-temperature structural components. Here, the interrelationships among localized forging strain, microstructure, texture, and creep anisotropy in a TA32 alloy are systematically investigated through a multi-scale approach integrating experimental characterization with first-principles calculations. Increasing forging strain progressively refines the duplex microstructure and strengthens a pronounced (11-20)//ST texture inherited from the parent (3 phase. While microstructural refinement enhances room-temperature tensile strength, the intensified texture introduces pronounced creep anisotropy at 550 degrees C, with the longitudinal direction exhibiting markedly superior creep resistance over the short-transverse direction. First-principles calculations reveal that this anisotropy originates from the intrinsic directional dependence of vacancy-mediated atomic diffusion: the (11-20) direction presents the lowest migration energy barrier, and its alignment with the ST loading axis accelerates dislocation climb, thereby reducing creep resistance. Consequently, the medium-strain region (0.75-0.90) defines an optimal forging processing window balancing strength, microstructural stability, and creep resistance.

This study systematically elucidates the microstructural evolution laws of AerMet100 steel under different thermal deformation conditions, employing multiscale characterization techniques, including optical microscopy, electron backscatter diffraction (EBSD), and transmission electron microscopy (TEM), to analyze microstructural features. Quantitative analysis focuses on lath martensite width, geometrically necessary dislocation density, kernel average misorientation, and grain orientation spread, revealing the correlations between these parameters and parent phase austenite, thereby providing new insights into the genetic mechanism of microstructure during deformation. Through orientation analysis of deformed microstructures, the nucleation mechanism of recrystallization is investigated; fine microstructural correlations between lath martensite and high-temperature austenite are established using TEM. A physically based cellular automaton model is developed, which couples dislocation density evolution to simulate recrystallization behavior under multiple thermomechanical processing paths. Its predictive capability is validated by EBSD measurement data of the original austenite. By tracking the evolution of dislocation configurations within cells during discontinuous thermomechanical processes, this study achieves cross-scale linkage of microstructural evolution across different thermomechanical stages, providing a theoretical framework and simulation tool for microstructural control of ultrahigh-strength steels under local heating and complex deformation conditions.

This study investigates the nucleation and recrystallization mechanisms in AerMet100 high-strength steel using advanced characterization techniques. Key microstructural indicators—inverse pole figures (IPF), geometrically necessary dislocation (GND) density, Taylor factor (TF), grain orientation spread (GOS), active slip systems, and lath martensite morphology—were analyzed. An Avrami-based phenomenological model was developed to examine the effects of deformation parameters on dynamic (DRX), sub-dynamic (SDRX), and static recrystallization (SRX) during plastic deformation. To enhance predictive accuracy, a hybrid modeling framework was introduced, combining a deep learning model (SSA-ATT-BiLSTM deep learning) with a white-box approach (explainable machine learning). This framework significantly improved prediction performance, increasing the coefficient of determination (R2) from 0.57168 to 0.92744 (phenomenological model) to 0.96696 and 0.97407 for grain size and recrystallized volume fraction, respectively. This optimized model provides a superior predictive capability for recrystallization evolution. By integrating physical metallurgy principles with machine learning, this study establishes a robust and accurate framework for predicting microstructural evolution in AerMet100 steel.