To address the limited availability of systematic design studies for a concurrent improvement in strength and ductility of long-period stacking ordered (LPSO)-containing Mg-RE-Zn alloys at engineering dimensions, an interpretable machine learning design framework is established in this study. By integrating computer vision with literature and our previous work, micrographs are automatically processed to extract quantitative descriptors of blocky LPSO phases, including volume fraction, size, morphology and dispersion. These LPSO-related descriptors are combined with RE/Zn contents, grain size, texture intensity and fabrication route as input features to develop predictive models for yield strength, ultimate tensile strength and elongation. Shapley additive explanations (SHAP) analysis reveals that grain size and LPSO volume fraction are the dominant factors governing strength, while elongation is most sensitive to the total RE content. Excessive RE content or LPSO volume fraction deteriorates ductility, whereas a uniform dispersion of blocky LPSO phases is beneficial for achieving a favorable strength and ductility synergy. Based on the proposed interpretable optimization framework, a promising composition region was identified for achieving improved strength and ductility synergy in Mg-RE-Zn alloys. Guided by the model predictions and further considering prior processing experience and casting feasibility, an alloy with nominal composition Mg-9.09Gd-3.12Y-2.10Zn was fabricated for experimental validation. After hot extrusion and peak ageing, industrial-scale plates with good formability and no obvious defects are successfully produced, exhibiting a yield strength of 351 ± 1 MPa, an ultimate tensile strength of 435 ± 2 MPa and an elongation of 14.3 ± 0.4%. This work demonstrates an effective integration of quantitative LPSO microstructural characterization with data-driven alloy design, providing a promising framework for guiding the optimization of strength and overall mechanical performance in industrial-scale Mg-RE-Zn alloys.

The effects of extrusion and annealing on the microstructure and mechanical properties of Al-Cu-Ce based alloys with coarse dendritic and equiaxed grains were systematically investigated. After deformation, both types of alloys exhibit a dual-phase heterogeneous lamellar microstructure: alternating layers of the Al-Al8CeCu4 eutectic region and the primary alpha-Al phase, and alternating layers of the fine-grained Al-Al8CeCu4 region and the coarse primary alpha-Al phase. The Al-Al8CeCu4 eutectic regions are distributed among the elongated equiaxed grains with different orientations, while multiple Al-Al8CeCu4 eutectic regions are embedded in a single coarse deformed primary alpha-Al dendrite. After annealing, the coarse deformed primary alpha-Al dendrites undergo complete recrystallization to form irregular coarse alpha-Al grains, which consume the fine-grained Al-Al8CeCu4 regions within them, whereas the deformed equiaxed grain microstructure remains almost unchanged. Notably, the fine intermetallic particles at the grain boundaries and L12-Al3(Sc,Zr) nanophases effectively inhibit recrystallization and dislocation recovery. Owing to the trade-off among the increments of various strengthening mechanisms, the yield strength of both alloys remains almost unchanged before and after deformation, while the strengthening effects of L12-Al3(Sc,Zr) nanophases and the refinement of primary precipitates induced by microalloying are still manifested. The fragmentation of coarse lamellar intermetallic phases alleviates stress concentration, modifies the orientation relative to the loading axis, delays crack initiation, and thus enhances the work-hardening capacity (UTS) and elongation of the alloys. However, the disruption of the continuous reticular intermetallic phase skeleton impairs its structural supporting effect on the material, increases the probability of grain boundary sliding, and causes premature failure of the alloys, thereby significantly degrading their elevated-temperature strength. This study clarifies the strategy for improving the elevated-temperature strength of heat-resistant Al alloys by adopting the microstructural template of a reticular intermetallic phase skeleton at grain boundaries and enhancing the thermal stability of theta'/theta"-Al2Cu phases via microalloying, which provides a clear direction for subsequent research.

This article aims to synchronously enhance the performance of plasma electrolytic oxidation (PEO) coatings under a wide range of engineering services whilst minimizing process energy consumption upon magnesium alloys as model system through guidance of interpretable machine learning. Experimental data were compiled from literature and our own work. Key PEO descriptors, including electrolyte formulation and electrical parameters, were extracted and quantified as input features. Predictive models were developed for film formation rate, surface porosity, and corrosion current density. Among the three selected regression algorithms, extreme gradient boosting (XGBoost) achieved the highest prediction accuracy. SHAP analysis was then applied to interpret the dominant factors governing coating performance. Film formation rate is mainly controlled by fluoride concentration, whereas surface porosity strongly depends on silicate concentration. Excessive silicate increases coating porosity, while an appropriate oxidation time favors improved corrosion resistance. Based on these insights, a Pareto optimization framework was employed to design a baseline electrolyte and electrical parameter set to validate their scientific soundness and generalization of the model. The coating produced under such a scheme exhibits a combination of high growth efficiency and superior corrosion resistance, with a film formation rate of 1.8 µm/min, a surface porosity of 5.4%, and a corrosion current density of about 1.3 × 10−8 A/cm². The proposed framework, which integrates interpretable machine learning with multi-objective optimization, offers an effective route for developing PEO process parameters, enabling the fabrication of low energy, high performance PEO coatings on magnesium alloys and providing a general data driven strategy for related engineering applications.

The poor fracture toughness limits the widespread application of high-strength cast Mg-Re-Zn alloys. Regulating the alloy microstructure, with phases such as α-Mg, blocky LPSO (long-period stacking order), and lamellar LPSO, offers various possibilities to enhance ductility by casting and heat treatment. This study categorizes different interface types concerning crack initiation, propagation, and ultimate fracture toughness. It distinctly presents the results of interface modulation related to alloy composition and heat treatment, elucidating the influence on crack initiation and propagation paths. Consequently, it proposes structural configurations rule and relevant heat treatment processes that can optimize and improve alloy fracture toughness. Blocky LPSO should have appropriate dispersion and size while avoiding lamellar LPSO.

Particle-stimulated nucleation (PSN) of dynamic recrystallization (DRX) is generally attributed to the accumulation of interfacial defects arising from plastic deformation incompatibility between a second phase and the surrounding matrix. When the second phase is highly deformable, however, reduced plastic strain mismatch may diminish the PSN effect. In this study, the influence of the long-period stacking ordered (LPSO) phase on DRX behavior in Mg alloys is quantitatively examined using hot-compression experiments over a range of temperatures. A statistical comparison between LPSO-containing and LPSO-free alloys reveals that the LPSO phase has a negligible effect on DRX at 400 °C, but significantly promotes DRX at 500 °C. By integrating diffraction-pattern preprocessing with full-pattern-matching spherical indexing, reliable phase- and grain-resolved orientation and strain analyses of both DRX grains and LPSO phases are achieved. At 400 °C, the LPSO phase deforms cooperatively with the Mg matrix owing to their comparable strengths, resulting in limited interphase strain mismatch and weak PSN activity. In contrast, at 500 °C, more rapid softening of the Mg matrix leads to reduced deformation of the LPSO phase, intensifying interphase strain incompatibility and thereby enhancing PSN-driven DRX. Additionally, LPSO grains accommodate deformation through grain-boundary dissociation at 500 °C, increasing particle number density and LPSO/Mg interfacial area, which further promotes DRX nucleation while suppressing grain coarsening. These findings elucidate the temperature-dependent role of deformable second phases in PSN-controlled DRX and provide guidance for designing thermomechanical processing routes and microstructures for improved Mg alloy performance.

The production of large-scale and high-strength Mg-RE alloy billets by semi-continuous casting is highly prone to destructive cold cracking, which makes the manufacturing of high-quality Mg-RE billets a challenge. In this work, the effects of casting temperature, casting speed, and cooling intensity on the temperature and stress fields were investigated using finite element (FE) casting simulation. The results show that with increasing casting speed from 20 mm/min to 45 mm/min, the temperature difference between the center and edge of the billet increases from 287 ℃ to 420 ℃, and the liquid sump depth increases from 93.5 mm to 252.7 mm. Increasing the value of the cooling intensity at the first cooling region (h1) significantly increases the temperature difference between center and edge of the billet inside the mould. When the values of h1 are 500 W/(m2·K), 1000 W/(m2·K) and 1500 W/(m2·K), the liquid sump depths are 199.1 mm, 183.5 mm and 177.1 mm, respectively. When the value of the cooling intensity at the second cooling region (h2) increases from 1000 W/(m2·K) to 4000 W/(m2·K), the temperature difference increases from 312 ℃ to 447 ℃, and the liquid sump depth decreases from 222 mm to 167 mm. The casting temperature have a small influence on the temperature gradient of the cross-section and the liquid sump depth of the billet. The results of the simulations of stress fields show that the interior of the billet is subjected to three-dimensional tensile stress, and reducing the casting speed and cooling intensity can significantly reduce the stress in the interior of the billet. The maximum principal stress at center of the billet can be adjusted to less than 150 MPa, which is lower than the tensile strength of the as-cast Mg-8.5Gd-2.5Y-1.5Zn-0.5Zr (wt

In this study, the microstructural evolution and corrosion product layer characteristics of Inconel 625 alloy subjected to different solution treatment temperatures in a simulated oilfield environment were investigated, and their influence on corrosion resistance was analysed. The results indicate that after solution treatment in the range of 950–1100 °C, the Mo-rich M6C carbides and Cr-rich M23C6 carbides gradually dissolve into the γ matrix, weakening the grain-boundary pinning effect of the carbides and promoting grain growth. Electrochemical measurements revealed that the corrosion current density and charge carrier density of Inconel 625 first decreased but then increased with increasing grain size. In the high temperature and high pressure CO2 environment, the alloy treated at 1050 °C has better corrosion resistance, which is attributed to the dissolution of M6C and M23C6 carbides into the matrix, resulting in an increase in the content of dense Cr2O3-based oxides. It effectively inhibits the penetration of Cl− and enhances the pitting corrosion resistance.

The effects of Mg and Si additions on the microstructure, nano-precipitate evolution, and mechanical performances of the Al-Cu-Ce-Mn-Sc-Zr alloy were systematically investigated. Mg exhibits low solid solubility in the Al8CeCu4 eutectic intermetallic phase, which refines the size of the 0 '-Al2Cu phase, while promoting the formation of the S-Al2CuMg phase within the alpha-Al matrix. However, due to the trade-off between the volume fractions of the S-Al2CuMg phase and 0 '-Al2Cu phase, coupled with the limited thermal stability of the S phase at temperatures exceeding 300 degrees C, the addition of Mg alone does not significantly influence the mechanical performances of the baseline alloy. The further addition of Si plays a multifaceted role: (i) releasing more Cu atoms through the formation of the Ce(SixAl1-x)2 intermetallic phase, thereby significantly increasing the volume fraction of the 0 '-Al2Cu phase; (ii) further refining the size of the 0 '-Al2Cu phase; (iii) suppressing the formation of the S phase; and (iv) promoting the formation of the T-Al20Cu2Mn3 precipitate. Additionally, the refinement effect of the L12-Al3(Sc,Zr) nanophase by facilitating the heterogeneous nucleation of 0 '-Al2Cu precipitates also enhances the overall precipitation strengthening effect. By maintaining a thermostable (semi-)continuous Al8CeCu4 network skeleton along the grain boundaries and enhancing the hardness of the alpha-Al matrix under both ambient-and elevated-temperature conditions, greater load transfer to the high-modulus eutectic intermetallic phase is achieved. This approach significantly improves the mechanical performance of the baseline alloy, with room-temperature tensile strength reaching approximately 400 MPa (an 11 % increase) and high-temperature tensile strengths of 250 MPa (a 20 % increase) at 300 degrees C and 175 MPa (a 17 % increase) at 350 degrees C. The incorporation of cost-effective microalloying additions (0.35 wt% Mg and 0.15 wt% Si) significantly enhanced the room-and high-temperature tensile performances of casting Al-Cu-Ce-based alloys. These outcomes afford critical insights and experimental evidence for further optimizing the tensile performances of traditional Al-Cu-based casting alloys designed for heat-resistant applications.

Mg-rare earth (RE)-Zn alloys exhibit strong composition-dependent microstructural evolution, in which Zn plays a critical role in regulating the formation of long-period stacking ordered (LPSO) phases and precipitation behavior. Dual-wire arc directed energy deposition (DWA-DED), with its capability for in-situ compositional tuning, provides an effective pathway for designing such composition-sensitive alloys. Based on Mg-9Gd-3Y (GW93) and Mg-9Gd-3Y-2Zn (GWZ932) feedstocks, an Mg-9Gd-3Y-1Zn (GWZ931) alloy was constructed via DWA-DED to obtain a microstructure containing both LPSO phases and β′ precipitates. Compared with GW93 lacking LPSO phases and GWZ932 with insufficient nanoscale precipitates in the matrix, GWZ931 develops a more coordinated microstructure, where the coexistence of LPSO phases and nano-precipitates is associated with a more favorable strength-ductility balance. Zn addition promotes the formation of thermally stable LPSO phases, which regulate rare-earth solute distribution, suppress abnormal grain growth, and facilitate a more uniform precipitation behavior during aging. By introducing circular oscillation, the lateral range in LPSO phase fraction across P1-P3 decreased from 11.1% to 3.9% in the solution-treated condition. The GWZ931 alloy after heat treatment achieves a yield strength of 253MPa, an ultimate tensile strength of 352MPa, and an elongation of 8.6%, showing a simultaneous improvement in strength and ductility compared to both reference alloys. These findings demonstrate that DWA-DED provides a flexible platform for rapid compositional screening and in-situ fabrication of intermediate compositions of high-performance Mg-RE-Zn alloys.

The present study investigates the enhancement of fracture toughness in Mg-RE-Zn alloys through a dual strategy: control of crystallographic texture and tailored distribution of long-period stacking ordered (LPSO) phase. Alloys with identical texture types but varying intensities and LPSO morphologies were fabricated via thermomechanical processing. Apparent fracture toughness was evaluated through threepoint bending tests, with crack propagation aligned parallel to the basal plane-a direction known for poor fracture resistance in textured magnesium (Mg) alloys. Crystallographic parameters, including twist angle phi, tilt angle theta, misorientation angle alpha, and geometrical compatibility factor m ', were extracted from EBSD data to analyze their roles in crack deflection and propagation. Results revealed that the strip-shaped LPSO phase significantly promotes crack path deflection and secondary crack nucleation, whereas the blocky LPSO phase was less effective. Moreover, twist angle phi showed a strong linear correlation with fracture toughness when LPSO volume fraction remained below 8 % and grain size exceeded 20 mu m. A predictive model based on twist angle phi and m was proposed to estimate the fracture resistance of textured Mg alloys. This work offers critical insights into microstructural design principles for enhancing the toughness of lightweight structural materials. (c) 2025 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

Mg-Li dual-phase alloys offer low density and good ductility but suffer from limited strength. This study investigates orientation-dependent deformation and slip transfer across the α-Mg/β-Li phase boundary in Mg-7Li alloy using micropillar compression tests. Single-phase α-Mg micropillars with angles of 0°, 45°, and 90° between the compression axis and the <0001> axis, and dual-phase micropillars with the same three orientations, are fabricated. Lithium addition dramatically lowers the critical resolved shear stress (CRSS) for prismatic ⟨a⟩ slip and pyramidal slip in α-Mg phase, resulting in a CRSSprismatic/CRSSbasal ratio of 1.11 and a CRSSpyramidal/CRSSbasal ratio of 4.1. Phase boundary strengthening strongly depends on the α-Mg orientation. In the 0° and 45° dual-phase micropillars, basal dislocations transfer directly across the phase boundary due to high values paired with the {110}⟨111⟩ slip systems in the β-Li phase. This causes negligible strengthening and agree well with the isostrain model. In the 90° dual-phase micropillar, prismatic ⟨a⟩ dislocations cannot transmit across the boundary. Instead, they cross-slip onto the basal plane, become immobile due to the low Schmid factor pf basal slip, and accumulate at the phase boundary. This generates HDI stress and contributes to phase boundary strengthening, thereby producing a “1+1>2” strengthening effect. Tailoring the α-Mg orientation to activate prismatic slip turns the phase boundary into an effective barrier, offering a promising route to achieve high strength in Mg-Li dual-phase alloys.

The effect of solution treatment on the microstructure and corrosion behaviour of Cu-alloyed low-density steel was investigated. The results indicate that solution treatment promoting re-dissolution of fine carbides and minimizing microgalvanic corrosion sites; facilitates austenite grain growth, which favors the formation of a dense Al-rich oxide film; and eliminates Cu segregation at grain boundaries, preventing intergranular corrosion. Cu addition enhances the content of protective Al2O3 and reduces detrimental Mn oxides in the passive film, suppressing active dissolution of the matrix. After solution treatment, the 1 wt% Cu specimen exhibits the optimal corrosion resistance, as evidenced by the highest charge transfer resistance and the lowest corrosion rate.

Tensile twinning plays a pivotal role in the plastic deformation of Mg alloys, and its nucleation is governed by the coupling of multiple microstructural factors. Focusing on pure Mg, we combine electron backscatter diffraction (EBSD) with machine learning to develop a predictive model that captures multivariate interactions controlling tensile twinning. Thirty-four microstructural descriptors were extracted, an Extreme Gradient Boosting (XGBoost) classifier was trained on 5669 grains strained to 1%, and the model was interpreted using Shapley Additive Explanations (SHAP). In addition to the Schmid factor (SF) for tensile twinning, the analysis reveals that grain size, the SF for slip, grain morphology, and neighboring grain attributes significantly influence tensile twin nucleation. Tensile twinning is favored in large, irregularly shaped grains and in grains located within neighborhoods that provide poor strain accommodation. Moreover, tensile twinning in low SF grains is not anomalous and can be attributed to the inability of strain accommodation to sufficiently release the local stress, leading to its accumulation near complex grain boundaries and thereby facilitating twin nucleation. External validation on AZ31 and GW93 alloys confirms strong predictive performance and transferability across distinct Mg alloy systems. This study provides data-driven insight into the nucleation of tensile twin in Mg alloys and establishes a practical framework for microstructure design and deformation control in the development of high-performance Mg alloys. (c) 2026 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

The contradiction between the strength and ductility of magnesium (Mg) alloys has become a theoretical obstacle and technical bottleneck in their research. The preparation technology of ultrafine grains/nanocrystals relying on severe plastic deformation deviates from actual industrial production, therefore alloying is currently a more practical choice. This work simultaneously promoted the strength and ductility of Mg-Gd-Y-Zn-Zr alloy by adding a trace amount of Er element (0.5 wt%). Er microalloying has little effect on grain size, texture, morphology and content of long-period stacking ordered (LPSO) structure, but significantly promotes aging precipitation, thereby substantially increasing the number density of beta' and reducing its size. The significantly refined beta' makes calculations based on the Orowan bypass mechanism less accurate, and more consideration should be given to linking the synchronous improvement of strength and ductility with the dislocation-shearing mechanism.

This study investigates the corrosion behavior of Al-Zn-Mg-Cu alloys treated by non-isothermal aging (NIA) in a simulated shallow oil and gas well high-pressure CO2 environment (1-4 MPa, 60 degrees C) and the effect of pressure on the dynamic behavior of the passivation film, using electrochemical techniques, scanning electron microscopy (SEM), electron probe microanalysis (EPMA), and transmission electron microscopy (TEM). The results show that the corrosion current density of the H10 sample treated by NIA at 4 MPa (1.07 x 10- 7 A/cm2) is an order of magnitude lower than that of the T6 sample (1.21 x 10-6 A/cm2), and its passivation film exhibits higher stability due to the uniform distribution of eta ' phases and the optimized grain boundary structure. The highpressure environment promotes CO2 dissolution to form H2CO3, which leads to environmental acidification and localized dissolution of the passivation film, causing the corrosion morphology to shift from uniform corrosion to pitting corrosion. In addition, under high pressure, the ratio of Al2O3/Al(OH)3 decreases, and the proportion of unstable hydroxides such as Zn(OH)2 and Mg(OH)2 increases, weakening the protective properties of film. This also accelerates the coarsening of eta phases, intensifies micro-galvanic corrosion, and accelerates the breakdown of the film, leading to alloy failure.

In the present work, four Mg-3Al-5Y, Mg-6Al-11Y, Mg-9Al-17Y, and Mg-11Al-21Y (wt.%) alloys, with different volume fractions of Al2Y phase, were fabricated by mechanical stirring casting and hot extrusion. The effect of Al2Y phase on the microstructure and deformation behavior of Mg-Al-Y alloys was investigated using the focused ion beam–digital image correlation (FIB-DIC) technique. The results show that as the volume fraction of the Al2Y phase increases, the strength of the Mg-Al-Y alloys continuously improves, which is primarily attributed to the coefficient of thermal expansion (CTE) strengthening mechanism. The Young’s modulus also increases, owing to the high modulus of the Al2Y phase, and the increase in modulus is more consistent with the prediction of the Reuss model. Notably, the Mg-9Al-17Y alloy achieves an optimal combination of yield strength (202.4 MPa), Young’s modulus (51.5 GPa), and ductility (7 %). The FIB-DIC technique highlights strain concentration at the Al2Y/Mg matrix interfaces and grain boundaries, where strain compatibility is influenced by adjacent grain orientations and phase interfaces mismatch. Additionally, the size, dispersion, and distribution of Al2Y phases play a crucial role in strain accommodation. This study provides valuable insights for the design of high-performance magnesium alloys with enhanced mechanical properties.

In this study, the corrosion properties of a novel Co40Cr20Ni30Al4.5Ti5Mo0.5 high-entropy alloy at different annealing temperatures were investigated through electrochemical techniques and tests conducted in an extreme environment of high-temperature and high-pressure CO2 containing 3.5 wt% NaCl. The results show that alloys annealed at temperatures ranging from 700 to 1000 degrees C recrystallized with different degrees. Notably, annealing at 800 degrees C significantly enhances corrosion resistance, as evidenced by a lower passive current density (i(pass) = 5.75 x 10(-7) A/cm(2)), wide passive potential range (Delta E = 716 mV(SCE)), and high pitting potential (E-pit = 500 mV(SCE)). Under extreme conditions of 200 degrees C and 6 MPa CO2, the alloy retains favourable mechanical properties and demonstrates exceptional corrosion resistance, can be attributed to the formation of nanoscale grain size (similar to 0.81 mu m) at 800 degrees C, a thicker and uniformly dense passive film (similar to 4.33 nm).

Integrating conventional forging with wire arc additive manufacturing (WAAM) enables the fabrication of magnesium-rare earth (Mg-RE) alloy components with improved mechanical performance and production efficiency, particularly for locally intricate structures. In this study, a Mg-9Gd-3Y-2Zn-0.5Zr (wt.%, GWZ932) alloy bulk sample was fabricated via multi-pass multi-layer WAAM deposition on an as-forged substrate. The microstructural evolution and deformation behavior in both the AM and interfacial regions were systematically investigated. Cyclic thermal input during deposition induced in-situ heat treatment effects, promoting the transformation of stacking faults into lamellar 14H-LPSO (Long-Period Stacking Ordered) phases in the AM region, while age-precipitated beta ' phases formed in the interfacial region subjected to intensified thermal cycling. The AM region exhibited a fine equiaxed grain structure with an average grain size (AGS) of 12.0 mu m, while the interfacial region showed further refined grains of 9.8 mu m. The interfacial region demonstrated higher microhardness of 83.8 HV and ultimate tensile strength of 271 MPa compared to the AM region. Digital Image Correlation (DIC) analysis reveals that the interface exhibits coordinated deformation without strain localization, confirming robust metallurgical bonding. These findings contribute to the scientific understanding of microstructure-property relationships and interfacial control in magnesium wire arc additive manufacturing, providing an integrated forming solution for large-scale lightweight complex components.

The necessary condition for using plastic forming to regulate microstructure is a sufficient understanding of the material's hot deformation behavior. This work systematically studied the mechanical response and micro- structural evolution of Mg-8Gd-5Y-1.5Zn-0.5Zr(-0.3Sn) alloys during hot compression, and established corresponding mathematical models, which provide data sources and theoretical support for subsequent plastic forming simulations and process parameter optimization. Sn microalloying induces the formation of numerous submicron sized (31 particles during hot compression, which is related to the ease of bonding between Sn and rare earth (RE) elements. The (31 particle swarm promotes recrystallization by activating the particle-stimulated nucleation (PSN) mechanism, so that the flow stress decreases to steady state with a greater magnitude after reaching its peak. Sn microalloying allows Mg-Gd-Y-Zn-Zr alloys with poor formability to achieve more effective grain refinement at relatively low strains.