The cooperative effect of microvoids and grain boundaries on the microplastic deformation behavior of a titanium alloy with a duplex microstructure under cyclic loading was analyzed based on the crystal plasticity finite element (CPFE) method. In this paper, the feasibility of the model is verified by contrasting the outcomes of the experiment and simulation. According to the results of the simulation, the stress gradient along the grain boundary increases as the distance between the microvoid and the grain boundary decreases. When the angle between the c-axis of the grain and the external force is 75 degrees, at which the grain boundary deformation is the easiest, the cumulative shear strain (CSS) surrounding the microvoid on the grain boundary reaches its maximum magnitude. The change trend of CSS and misorientation is the same when the dominant slip system is unaltered, and it is opposite when the dominant slip system changes. Additionally, the average stress level on the grain boundary increases with increasing microvoid size, which is significantly greater than that in the grain. The proposed duplex microstructure model of titanium alloy with microvoids can further explore the cooperative effect of microvoids and grain boundaries to study the fatigue behavior of duplex titanium alloy.

The complex geometries of turbine blades require alloys to deliver excellent overall performance across distinct surface orientations; in addition to mechanical anisotropy, oxidation behavior warrants equal attention. By employing a suite of characterization techniques including XPS, FIB-TEM, and SEM, this study systematically investigates the oxidation behavior and elemental diffusion mechanisms of the second-generation La-modified CMSX-4 superalloy across distinct surface orientations. The results indicate that the comprehensive oxidation resistance ranking of CMSX-4 alloy with three surface orientations is (100) > (111) > (110). During the initial stage of oxidation, the higher proportion of gamma' phase on the (100) plane surface leads to the formation of more Al2O3 in the alloy surface layer. Additionally, the shorter gamma'/gamma interface diffusion path on the (100) plane facilitates the diffusion of Al, Ti, and Ta from the matrix to the surface oxide layer, forming a stable oxide layer structure, thereby enhancing the alloy's oxidation resistance. However, in the later stages of oxidation, the higher atomic stacking density of the (111) plane results in superior oxidation resistance compared to the (110) plane. The results can offer a theoretical basis for the manufacturing and service of single-crystal blades with complex shapes.

The Hugoniot elastic limit (HEL) serves as the critical stress threshold demarcating the transition from purely elastic to elastoplastic response under dynamic loading. Accurate determination of the HEL is essential for understanding dynamic mechanical behavior. Traditionally, the HEL is derived from the "double-wave" structure of free-surface velocity profiles. However, wavefront dispersion of the elastic precursor and non-steady-state effects in short-pulse laser-driven experiments introduce systematic deviations in longitudinal sound velocity measurements, thereby limiting precise HEL determination. To address these challenges, a self-consistent interpretation method integrating macroscopic conservation laws with microscopic thermoelastic simulations is established. Based on momentum conservation, this work establishes a self-consistent equation that relates axial stress to longitudinal sound velocity and particle velocity. This equation corresponds to the process in which high-stress perturbations catch up with low-stress wavefronts. Using the experimentally measured elastic-precursor particle velocity as the constraint, the HEL and the corresponding longitudinal sound velocity can be determined self-consistently by iteratively solving this equation, without relying on ambiguous wavefront arrival-time measurements. To support this procedure, a continuous sound velocity-pressure constitutive relationship is derived from a high-pressure thermoelastic dataset spanning 0-1000 GPa, constructed using density functional theory combined with the mean-field potential (MFP) method and the quasi-static approximation (QSA). The validity of this approach is verified using diamond as a benchmark material. The predicted elastic moduli agree with static compression data within 0.4% relative deviation up to 15 GPa. For gas-gun experiments with peak stresses reaching 1 TPa, the reinterpreted HEL values show less than 2% relative deviation from standard experimental benchmarks. These results quantitatively characterize the crystalline anisotropy, where the longitudinal sound velocity follows the sequence [111] > [110] > [100]. For laser-driven experiments where non-steady-state attenuation previously caused systematic underestimation, the HEL values are corrected upward by 8%-13%, reconciling discrepancies between different loading platforms. This hybrid approach enables the retrospective correction of non-ideal experimental effects through solely through data reanalysis, thereby providing high-precision dynamic constitutive parameters under extreme conditions without requiring specialized experimental configurations. The datasets presented in this paper are openly available at https://doi.org/10.57760/sciencedb.j00213.00274.

TiAl/Ti2AlNb laminated composites were fabricated by vacuum hot-pack rolling, forming three distinct interfacial regions: brittle regions I (βo + α2 + γ + ω) and II (βo/B2 + α2 + ω), and ductile region III (O). Multiscale characterization combining digital image correlation and in-situ three-point bending tests revealed that the laminated composites exhibit a 2.0–2.5-fold improvement in fracture toughness compared with monolithic TiAl alloy. This enhancement arises from the synergy between intrinsic and extrinsic toughening mechanisms. The intrinsic toughening is associated with slip deformation of B2 grains in the Ti2AlNb layer and grain-boundary obstruction to crack propagation, whereas the extrinsic toughening originates from interfacial crack branching in regions I and II, together with crack deflection and blunting in region III. Furthermore, the critical role of the pre-notch position was emphasized. When the notch terminates in the Ti2AlNb layer, interfacial crack branching effectively alleviates stress concentration, increasing KQ to 40.2 MPa m1/2. Conversely, when the notch terminates in the TiAl layer, rapid crack initiation caused by the low damage tolerance of TiAl triggers premature structural instability, reducing KQ to 29.5 MPa m1/2. These findings provide guidance for interfacial design and toughening optimization of TiAl-based laminated composites.

This study deciphered the influence of lamellar alpha ( alpha l ) colony parameters on impact toughness of alpha+ beta titanium alloy with lamellar microstructure. alpha+ beta titanium alloy Ti-5Al-7.5V-0.5Mo-0.5Zr-0.5Si was beta treated and cooled under different cooling rates to obtain alpha l colony with diverse morphology and size. Unotch Charpy impact test revealed that the impact toughness increased with decreased cooling rate and consequent alpha l colony coarsening. Impact load-displacement curves demonstrated that alpha l colony coarsening simultaneously enhanced both impact crack initiation energy and crack propagation energy. In the crack initiation region near U-notch, slip trace analysis indicated that coarse alpha l colony extended dislocation mean free path and triggered multiple slips, which facilitated plasticity prior to U-notch cracking and enhanced Wi . Furthermore, as evidenced by Focus Ion Beam-Transmission Electron Microscopy, the nucleation of {101 2} <1 011 > twin in coarse alpha l colony mitigated deformation heterogeneity, acted as prismatic slip pathway, and provided sustainable < c + a > dislocation sources, thereby further delaying U-notch crack initiation and enhanced Wi . Conversely, fine alpha l colony restrained dislocation mobility and inhibited twin nucleation, leading to inferior U-notch plasticity and resultant low Wi . From U-notch cracking to final fracture, the sustained crack blunting due to substantial plastic deformation of coarse alpha l along the crack path, as well as crack deflection and branching between adjacent coarse alpha l colonies, synergistically enhanced Wp . Conversely, fine alpha l colony impaired the plasticity along the crack path and restrained crack deflection, which was inconducive to Wp . In summary, alpha l colony coarsening played a crucial role in activating multiple toughening mechanisms during both crack initiation and propagation to achieve desirable impact toughness in alpha+ beta titanium alloys with lamellar microstructure. (c) 2025 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

This study combines nanoindentation and crystal plasticity finite element (CPFE) simulations to determine the micro-nano mechanical properties and constitutive parameters of γ and α2 phases in TiAl alloys. Phase-specific parameters were successfully calibrated through inverse analysis, validated by excellent agreement between simulated and experimental curves. Both phases showed orientation-dependent hardness, and the γ phase also exhibited orientation-dependent elastic modulus. The intrinsic size-independent hardness H0 was determined through indentation size effect analysis. As Al content increases from 43% to 45%, γ-phase hardness rises from 3.470 GPa to 4.625 GPa while α2-phase hardness increases from 5.801 GPa to 6.734 GPa, with corresponding critical resolved shear stress (CRSS) values increasing by 43% and 50%, respectively. Conversely, increasing Mo content from 0.5% to 1.5% enhances γ-phase hardness from 3.629 GPa to 4.851 GPa but reduces α2-phase hardness from 7.326 GPa to 6.052 GPa, while similarly elevating CRSS values by 43% and 50%. Further analysis reveals that Al content increase elevates γ-phase elastic modulus by14.3% but reduces α2-phase modulus by 8.7%, whereas Mo content increase significantly enhances α2-phase modulus by 2.6% without substantially affecting γ-phase modulus. This integrated approach provides quantitative insights into composition-dependent mechanical behavior of individual phases in TiAl alloys.

Rare-earth (RE) zirconates and tantalates are promising candidates for next-generation thermal barrier coatings (TBCs) due to their high-temperature stability and low thermal conductivity. However, the substantial compositional complexity introduced by multiple RE element substitutions poses significant challenges for systematic property optimization. To address these challenges, a high-throughput, data-driven computational framework was employed to systematically investigate and compare structural stability, thermodynamic properties, lattice thermal conductivity (kappa(L)) and fracture toughness (K-IC) of RE2Zr2O7 and RE3TaO7 oxides (RE = Sc, Y, La similar to Lu) in their pyrochlore and Weberite-type structures, respectively. kappa(L) and intrinsic K-IC were systematically evaluated using phonon-scattering and Griffith-based models. The results reveal that RE3TaO7 exhibits consistently lower kappa(L) than RE2Zr2O7 due to its low symmetry, heavier atomic masses and higher structural disorder. Interestingly, theoretical predictions indicate slightly higher intrinsic K-IC in RE2Zr2O7, which is attributed to its ordered vacancy sublattice and symmetric bonding. In contrast, experimental data often report superior K-IC for RE3TaO7, likely due to extrinsic microstructural effects not captured in idealized calculations. Correlation and SHapley Additive exPlanations analyses further reveal that bond energy, charge disorder and bond-length heterogeneity are key descriptors governing kappa(L) and K-IC. These findings provide mechanistic insight into structure-property relationships and offer a predictive framework for the rational design of RE oxide TBC materials.

Rapidly solidified Al-Mg-Si alloys are highly desirable in the aerospace and automotive industries because of their excellent potential in terms of light weight and high performance, but the unclear synergistic effects of cold rolling deformation and solution treatment temperature on their microstructure and mechanical properties limit the optimization of the strength-ductility balance for industrial applications. On this basis, the effects of rolling deformation and solution treatment temperature on the microstructural changes and associated mechanical properties of Al-Mg-Si alloys were investigated. The rapidly solidified Al-Mg-Si alloy was subjected to cold rolling with deformation degrees of 50%, 65%, and 80%, followed by solution treatment at 530, 550, and 570 °C for 5 min and artificial aging at 75 °C. The microstructural characteristics were analyzed via EBSD, SEM, and XRD, whereas the mechanical properties were evaluated through tensile tests and Vickers hardness measurements. The results indicate that, after T6 heat treatment, alloys with greater rolling deformation exhibit less Si enrichment at the grain boundaries and finer grains. However, an increased solution temperature has both positive and negative impacts on the material strength. At 550 °C, complete recrystallization and uniform dispersion of the Mg _2 Si and Mg _5 Si _6 phases are promoted, whereas at 570 °C, abnormal grain growth in the medium-deformation samples is induced. Ultimately, the optimal rolling deformation and solution temperature for the good strength-ductility trade-off of the alloy were ascertained. The alloy achieves the optimal strength-ductility balance at 80% rolling deformation and a 550 °C solution temperature, exhibiting a yield strength of 117.0 MPa, a tensile strength of 230.3 MPa, and an elongation of 32.7%.

The effects of alloying elements on hydrogen embrittlement (HE) resistance of nickel-based single-crystal superalloys (Ni-SXs) are investigated through first-principles calculations and macro-mechanical experiments. The segregation of hydrogen at the gamma/gamma ' interface leads to the degradation of interfacial cohesive strength and vacancy formation energy. Analysis of bonding charge density reveals that hydrogen-induced decohesion stems from the weakening of interatomic bonds between the first-nearest-neighboring atoms. The tensile-fracture morphology demonstrates that the growth and coalescence of micro-voids near crack tips promote hydrogen-assisted crack propagation. Among the investigated alloying elements, Re preferentially segregates at the interface and exerts pronounced inhibition of hydrogen-enhanced decohesion and vacancy formation through the formation of strong Ni-Re bonds. Consequently, Re improves the HE resistance of Ni-SXs by inhibiting hydrogen-induced cracks and micro-voids. The current work extends the understanding of HE mechanisms in Ni-SXs and provides theoretical guidance for designing superalloys with exceptional HE resistance.

The high-temperature oxidation resistance of Ni-based single crystal superalloys is paramount to their service reliability. However, conventional ex-situ characterization techniques struggle to capture the transient behavior during the initial stages of oxidation, often obscuring the underlying nanoscale kinetic processes. To this end, we utilized in situ transmission electron microscopy (TEM) to directly observe the oxidation behavior of CMSX-4, a typical second-generation nickel-based single crystal superalloy, during continuous heating. The results indicate that during the gradual temperature increase, the gamma phase preferentially oxidizes, while the gamma' phase, as an intermetallic compound, experiences substantial oxidation only at 600 degrees C. At 800 degrees C, the gamma' phase rapidly oxidizes, driven by the outward diffusion of Ni and Co into the gamma matrix, which results in the extensive formation of NiO and CoO. Furthermore, complementary ex-situ bulk oxidation tests at 1000 degrees C were incorporated to reveal the macroscopic multi-stage kinetics governed by the development of a multilayered scale and the spallation induced by an intermediate refractory-rich oxide band. The selective oxidation of the two phases, along with the observed crystallographic orientation-dependent oxidation behavior and cross-scale correlations, provides valuable insights for designing high-temperature alloys with enhanced oxidation resistance.

This study investigates the microstructural evolution and mechanical properties of a novel Ti-44Al-1.5Cr-0.5Re alloy sheet processed by hot rolling at temperatures ranging from 1050 degrees C to 1250 degrees C. Results demonstrate that rolling at 1050 degrees C, near the eutectoid temperature, leads to significant grain refinement with an average grain size of 2.31 & micro;m, attributed to the combined effects of particle-stimulated nucleation (PSN) and alpha 2 twinning-induced fragmentation. The refined microstructure contributes to exceptional superplasticity at 800 degrees C, exhibiting an elongation of 140% alongside a tensile strength of 472 MPa. Microstructural analysis reveals that the grain refinement mechanism under low-temperature, high-stress rolling involves the decomposition of alpha 2 and (3o phases into finely dispersed particles, which promote dynamic recrystallization of the gamma phase via PSN effect, while repeated alpha 2 twinning leads to continuous grain subdivision. This work provides a viable low-temperature rolling strategy for producing fine-grained TiAl sheets with excellent superplasticity, offering significant potential for energy-efficient forming of aerospace components.

Near-α titanium alloy sheets are susceptible to localized failure during complex forming processes, primarily due to their strong initial textures. Elucidating the evolution mechanisms of such strong textures and the competing behaviors of slip systems under varying stress states is crucial for overcoming current bottlenecks in complex forming. In this study, the distinct deformation behaviors of Ti65 alloy sheets subjected to uniaxial tension and three-point bending were systematically investigated by combining experimental characterizations with Abaqus-VPSC multiscale simulations. The results demonstrate that under uniform tensile loading, the mechanical anisotropy is mainly governed by the dependence of the Schmid factor on the initial crystallographic orientation. Deformation is predominantly accommodated by prismatic slip, resulting in texture feature stability. Conversely, the geometric constraints and strain gradients introduced during bending deformation increase the activation tendency of pyramidal slip to accommodate the c-axis deformation of grains. This transition in the dominant slip mode is evident on the extrados of the bent sheet, reducing the stability of the initial texture. Furthermore, the crystal plasticity parameters calibrated using uniaxial tensile data reasonably predicted the heterogeneous deformation characteristics on the intrados and extrados of the bent sheet. This study provides an important theoretical basis for texture control during the forming of complex titanium alloy components.

Superlubricity in two-dimensional van der Waals materials arises from moire superlattices (MSL) that suppress sliding friction via periodic potential cancellation. However, a structure-property correlation linking the geometric and physical characteristics of MSL distortions to sliding energy barrier and tribological performance remains lacking. Here, the tribological performances of bilayer transition metal dichalcogenides (TMDs) including MoSJ, WSJ, MoSeJ, and WSeJ are systematically investigated at twist angles of 0 degrees, 13.17 degrees, 21.79 degrees, and 32.20 degrees. The results demonstrate that the sliding energy barrier is governed by the interplay among MSL-induced lattice distortion, electronic localization, and interlayer-spacing modulation. Specifically, the intrinsic bonding strength is found to be highly sensitive to both chalcogen species and twist angles. While Se-containing systems exhibit stronger intralayer electron localization and enhanced interlayer charge-density fluctuations, S-based systems display comparatively weaker electronic modulation. At 13.17 degrees, pronounced d-orbital localization strengthens interlayer coupling, resulting in the highest sliding energy barriers. In contrast, at 21.79 degrees and 32.20 degrees, the reduced area of strongly coupled stacking regions, together with the enlarged interlayer spacing, weakens interlayer interactions, thereby facilitating low-energy sliding pathways. Accordingly, WSJ at 32.20 degrees is predicted to exhibit the lowest sliding barrier, owing to an optimal balance between charge localization and interlayer separation. By establishing a quantitative correlation among sliding energy barriers, interfacial orientations, and material compositions, this study elucidates the MSL-driven lubrication mechanism and provides theoretical guidance for the rational design of advanced lubricants.

Furazanopyrazine-based energetic compounds were developed through a substitution-nitration strategy combining flexible biogenic amine side chains with nitramine modification. Structural and thermal analyses revealed that side-chain flexibility effectively tunes crystal packing and phase behavior. Among compounds I-VII·H2O, compound II exhibited the most favorable melt-cast characteristics, with a melting point of 89 °C, competitive detonation performance, and acceptable sensitivities. These results offer a useful design strategy for fused-ring melt-cast energetic materials.

To explore low-melting zwitterionic energetic materials with high energy density, this study used 4,5-diamino-1-(2-hydroxyethyl)pyrazole sulfate as the starting material and controllably synthesized two pyrazole-based zwitterionic energetic materials (2 and 3) via a one-step straightforward approach. Single-crystal X-ray diffraction verified that compound 3 possesses a crystal density of 1.842 g cm-3 and exhibits a zero-oxygen balance. Thermal analysis showed that the melting points of 2 and 3 are 99 degrees C and 118 degrees C, with decomposition temperatures of 181 degrees C and 196 degrees C, respectively. Calculations using EXPLO5 V6.05 gave detonation velocities of 8081 m s-1 (2) and 8901 m s-1 (3), and detonation pressures of 26.54 GPa (2) and 35.03 GPa (3). BAM tests indicated impact sensitivities (IS) of 6 J (2) and 4 J (3), and friction sensitivities (FS) of 160 N (2) and 240 N (3). NASA CEA calculations suggest that compounds 2 and 3 possess promising gas-generation and energy-release potential for energetic formulation design. The as-synthesized zwitterions exhibit excellent laser responsiveness and can act as promoters for igniting AP or DATNBI. This work provides new insights into the design of low-melting zwitterionic energetic materials and laser-ignition promoters.

This study utilizes the temperature-dependent reduction of stacking fault energy in FCC high-entropy alloys (HEAs) to regulate deformation defects through cryogenic rolling and subsequent annealing, thereby enhancing the strength-ductility synergy of L12-strengthened HEAs. A precipitation-strengthened HEA, Al5Ti5Cr20Co35Ni34.9B0.1, was newly designed as a model system. Cryogenic rolling introduced a high density of dislocations and stacking faults, while subsequent annealing enabled partial recovery and rearrangement of these defects. The optimized sample (CRA20%) achieved an excellent balance of yield strength (1486 MPa) and elongation (12.1 %), superior to that of the room-temperature-rolled counterpart. Microstructural analysis revealed that the synergistic interaction between dislocations and stacking faults dominated the strengthening behavior. These findings demonstrate that defect engineering via cryogenic thermomechanical processing effectively tailors the mechanical response of L12-strengthened HEAs. The present work provides new insights into controlling deformation defects in precipitation-strengthened alloys and offers valuable insights for further strengthening of other alloys.

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.

In this work, we report a cellular-reaction-assisted strategy that enables successful rolling of a Ti-44Al-1.5Cr-0.5Re (at.%) alloy sheet at 950°C while achieving an exceptional strength-ductility synergy. The cellular-reaction-derived pearlite-like microstructure contains discontinuously dispersed β0 phase, abundant phase interfaces, and pre-existing planar defects. During rolling, these microstructural features promote lamellar bending, interfacial separation, defect accumulation, and particle-stimulated nucleation-assisted recrystallization, leading to an ultrafine near-γ microstructure with an average γ grain size of 0.84 μm after 80% reduction. The rolled sheet exhibits a room-temperature tensile strength of 1378 MPa with 1.42% elongation, mainly owing to ultrafine-grain strengthening and deformation-induced stacking faults, twins, and 9R/long‑period stacking‑ordered-related structures. At 800°C, the alloy shows a tensile strength of 476 MPa and an exceptional elongation of 283%. This superior high-temperature ductility originates from the cooperative deformation of the heterogeneous microstructure, where coarse γ grains provide strain hardening, fine γ grains accommodate deformation through grain-boundary-mediated processes, and boundary discontinuous dynamic recrystallization governs flow softening. These results highlight cellular reaction as an effective route to reconcile low-temperature rollability with strength-ductility synergy in TiAl alloy sheets.

High-entropy alloys (HEAs), with their unique multi-principal element design philosophy, have opened up an exceptionally vast compositional space, breaking through the performance limitations of conventional alloys. As an emerging class of energy materials, HEAs have demonstrated tremendous potential in extreme environment service and structural engineering applications. However, the huge combinatorial space and the complex nonlinear coupling among composition, processing, microstructure, and property make traditional trial-and-error approaches inefficient for discovering high-performance alloys. As a data-driven paradigm, machine learning (ML) provides an effective solution to the "combinatorial explosion" problem in HEAs design by enabling efficient exploration of high-dimensional spaces and revealing hidden structure-property relationships. As HEAs design shifts from experience-driven exploration to data-driven discovery, this review systematically examines the challenges, emerging trends, and future directions of ML in composition screening, microstructure evolution prediction, and mechanical property optimization. For the complexity of multi-principal element systems, ML models based on physics-informed feature engineering and phase stability prediction have successfully identified feasible compositional regions. Combined with active learning and multi-objective optimization, ML has promoted a shift from single-point prediction to closed-loop discovery. At the microscale, surrogate models integrating multimodal characterization and processing parameters offer new ways to quantify processing-microstructure relationships and inversely design thermomechanical pathways. Moreover, by introducing physics-based constraints and uncertainty quantification, ML has significantly improved the interpretability and extrapolation of predictions for strength, ductility, and fracture behavior. With the deep integration of multiscale simulation and large language model technologies, the data-driven paradigm is evolving from an auxiliary tool into a core engine for precise HEAs design and engineering implementation.