Porous structures are extensively utilized in lightweight manufacturing fields such as electronics and aerospace for heat dissipation. Due to the high thermal conductivity of copper alloys, powder adhesion during the laser powder bed fusion (L-PBF) process is a significant issue. Addressing the adhesion of unmelted powder on formed samples is crucial for ensuring the quality of porous structures. This study investigates the precise fabrication of CuCrZr alloy porous structures using L-PBF technology, and designs porous structures with a 20% volume fraction and varying cell sizes. To improve the quality of samples fabricated by L-PBF, plasma polishing was applied to the formed samples. Through subsequent heat treatment of the plasma-polished porous samples, mechanical properties and microstructures were analyzed. The experimental results show that plasma polishing reduces surface roughness by over 70%, significantly improving forming quality. The compressive strength reached a maximum of 332 MPa after heat treatment with a cell size of 2 mm, an increase of 79% compared to post-plasma polishing. Microstructure observations revealed that Cr precipitated after aging treatment, causing precipitation strengthening, which is a key factor in the improvement of mechanical properties. This research provides a theoretical basis for the post-processing of CuCrZr porous structures based on L-PBF technology.

This study proposes a novel approach for identifying corrosion types in AZ31 magnesium (Mg) alloy by combining electrochemical noise (EN) analysis with deep transfer learning. The EN signals from AZ31 under four distinct corrosion types including passivation, pitting corrosion, filiform corrosion, and the mixture of filiform and pitting corrosion, were acquired. Two types of EN-derived images, namely continuous wavelet transform (CWT) time-frequency images and recurrence plots, were generated as inputs to a ResNet18-based convolutional neural network. The model was trained and evaluated under multiple dataset sizes controlled by overlap rates. Results demonstrate that the CWT time-frequency image input significantly outperforms recurrence plots, achieving a testing accuracy of 98.03 +/- 0.87% at the highest overlap rate of 0.875, compared to 94.07 +/- 1.21% for recurrence plots. Furthermore, the deep learning model exceeded traditional random forest classifiers using handcrafted statistical or discrete wavelet features, with near-perfect classification accuracy across all four corrosion categories. Gradient-weighted Class Activation Mapping (Grad-CAM) and t-SNE visualizations confirmed that the model effectively focuses on discriminative time-frequency regions relevant to each corrosion type. This work demonstrates the potential of deep transfer learning combined with EN image representation as an effective tool for corrosion type identification in AZ31 Mg alloy under controlled laboratory conditions, providing a foundation for future development toward practical corrosion monitoring applications.

Thin-walled Mg-8.5Gd-2.5Y-1.8Zn-0.5Zr (GWZ932) alloy component was successfully fabricated by the cold metal transfer (CMT) based wire-arc additive manufacturing (WAAM) process. Considering the significant influence of secondary phases on mechanical properties, we regulated the secondary phases through heat treatment. As-deposited sample exhibits the typical layered microstructure with alternating coarse/fine grains, along with a lot of Mg3(RE,Zn) eutectic phases at grain boundaries (GBs). After solid-solution treatment, these eutectic phases are transformed into coarse X phase at GBs and fine lamellar 14H long period ordered stacking (14H-LPSO) phases in grain interiors. Further peak-aging induces amounts of prismatic beta ' phases precipitated in the alpha-Mg matrix, which produces the strong precipitation hardening effect. Note that prismatic beta ' phases are perpendicular to basal 14H-LPSO phase in space, which can form a closed space that blocks dislocation motions more effectively. Thus, peak-aged sample exhibits a high tensile strength of (314 +/- 3) MPa and an acceptable ductility of 4.3% +/- 0.6%, which outperforms most Mg-Gd-Y series alloys prepared by WAAM reported previously. Our work provides a basis for forming thin-walled Mg-Gd-Y series components with high strength via WAAM process, but the deposition process should be further optimized. (c) 2025 Chinese Society of Rare Earths. Published by Elsevier B.V.

Addressing the prevalent issues of solution non-uniqueness, strong parameter correlations, and highly disparate sensitivities in the inversion of Johnson-Champoux-Allard (JCA) parameters for additively manufactured triply periodic minimal surface (TPMS) acoustic metamaterials, this study proposes a non-acoustic parameter inversion method that integrates multi-response residual constraints, characteristic-length reparameterization, and multi-start sequential optimization. Three typical TPMS topologies-Diamond, Gyroid, and Primitive-are selected to characterize the acoustic structures. A common characteristic length L0 and dimensionless shape factors c and t are introduced to reparameterize the parameter space. The objective function is formulated as the measurement-variance-weighted mean squared error of the sound absorption and reflection coefficients, augmented by an acoustic impedance term constructed from relative residuals to mitigate low-frequency bias. A Darcy low-frequency prior soft constraint, weighted by sensitivity within sensitive frequency bands, is further incorporated to suppress the non-uniqueness of flow resistivity inversion. The inversion procedure generates 50 initial parameter sets via Latin hypercube sampling, ranks them by the objective function, selects the top 20 as multi-start points, and refines the solutions through sequential quadratic programming with a three-stage sequential Tikhonov regularization. Results demonstrate that the residuals between inversion predictions and impedance tube measurements remain within ±0.04 over the entire frequency range. Parameter identifiability analysis, correlation and well-posedness assessments, and finite element simulations jointly confirm the uniqueness and physical consistency of the inverted parameters. The proposed inversion framework provides a theoretical and numerical basis for the parametric design and performance evaluation of TPMS sound-absorbing metastructures.

Orthorhombic n-type BiSbSe3 possesses a theoretically promising thermoelectric performance in single-crystalline form. However, orthorhombic BiSbSe3 is stable only at high temperatures but thermodynamically unstable at room temperature. While orthorhombic BiSbSe3 polycrystals can be synthesized via rapid quenching to kinetically preserve this metastable phase, single-crystal growth demands slow cooling to enable near-equilibrium atomic incorporation at the growth front. Resolving the room-temperature thermodynamic instability of orthorhombic BiSbSe3 is an essential precondition for unlocking its thermoelectric potential. In this work, we successfully realized thermodynamic stabilization of the orthorhombic BiSbSe3 at room temperature through chemical composition optimization. Alloying with 15% sulfur (S) enables reproducible, quench-free synthesis of pure orthorhombic BiSbSe3, opening a viable pathway toward single-crystal growth and full realization of its thermoelectric potential. Building on this, we conducted a systematic investigation into the effects of halogen (Cl, Br, and I) doping on thermoelectric transport of n-type phase-stabilized orthorhombic BiSbSe3 polycrystals. The optimized BiSbSe2.52S0.45Br0.03 achieves a peak ZT of ∼1.0 at 773 K and a single-leg conversion efficiency of ∼6.1% at a temperature difference of ∼474 K, demonstrating that our phase-stabilization approach does not compromise the promising thermoelectric properties of orthorhombic BiSbSe3, thereby paving the way for anticipated high performance in high-quality single crystals.

High-entropy alloys (HEAs) exhibit unique mechanical properties, including high hardness, exceptional thermal stability, and good corrosion resistance, making them promising candidates for wear-resistant applications. However, systematic investigations of their tribological behavior at the atomic scale remain limited. In particular, the influence of Ti content on the friction and wear mechanisms of FeNiCrCoTi-based HEAs is still not well understood. This study investigates the effects of titanium content (0-20%) and indentation depth (8-14 & Aring;) on the tribological behavior and deformation mechanism of FeNiCrCoTiX high-entropy alloys using Molecular dynamics (MD) simulation. The findings show that the coefficient of friction for T10 (20% Ti) is 0.67 higher than that for T0 (0% Ti), and that both the number of wear atoms and the wear rate increase with Ti content. This is because increasing Ti content intensifies lattice distortion because of atomic size mismatch, which decreases the FCC phase while promoting the formation of BCC and other phases. This microstructural transformation lowers the total plastic deformability of the material. Additionally, the coefficient of friction reaches a maximum of 1.661 at an indentation depth of 14 & Aring;. As the indentation depth increases, the depth of the deformed region increases by 18 & Aring; and its width by 13 & Aring;. This is because deeper indentation depth enlarges the contact area between the abrasive and the alloy, inducing more severe subsurface lattice damage, which considerably increases the lateral friction force. Finally, with increasing sliding distance, the accumulated plastic deformation from sustained shearing and the number of wear atoms both grow substantially. This study aims to elucidate the tribological properties and underlying mechanisms of FeNiCrCoTi alloys, providing insights that support their potential use in wear-resistant applications.

ABSTRACT Niobium‐based refractory alloys are promising candidates for high‐temperature aerospace structures, yet their limited ambient‐temperature ductility and poor processability remain major barriers to broader implementation. Here, Nb521 alloy was fabricated by laser powder bed fusion (LPBF), and the effects of processing conditions and subsequent hot isostatic pressing (HIP) on microstructural development and mechanical response were systematically examined. The as‐printed alloy exhibited a heterogeneous grain structure composed of columnar and equiaxed grains, together with pronounced solute segregation and dense dislocation substructures generated by rapid solidification. HIP promoted chemical homogenization, reduced the fraction of low‐angle grain boundaries, weakened the crystallographic texture, and induced a partial tetragonal‐to‐monoclinic transformation of dispersed ZrO 2 particles. These microstructural modifications led to a marked improvement in the strength‐ductility balance. In particular, after HIP treatment, the specimen fabricated with a laser power of 240 W and a scanning speed of 500 mm s −1 (LED = 480 J m −1 ) exhibited an ultimate tensile strength of 581.9 ± 2.98 MPa, a yield strength of 442.2 ± 8.66 MPa, and a tensile elongation of 22.3% ± 0.62%. Quantitative strengthening analysis indicates that the yield strength arises from the combined contributions of lattice friction, grain‐boundary strengthening, dislocation strengthening, and precipitation strengthening. The precipitation contribution is governed predominantly by Orowan bypassing, with an additional contribution from particle shearing, enabling simultaneous strengthening and ductility retention. These findings clarify the microstructural origins of the enhanced mechanical performance of LPBF‐processed Nb521 alloy and provide guidance for designing additively manufactured niobium‐based alloys with improved strength‐ductility synergy.

Rational interlayer cooling time management emerges as a critical yet underexplored parameter for controlling microstructural evolution and mechanical performance in wire-arc additive manufacturing (WAAM) of rare-earth magnesium alloys. The present work systematically investigates, through integrated experiment and simulation, how varying cooling intervals (45–180 s) affect grain morphology, phase precipitation, and tensile properties in CMT-WAAM fabricated Mg-Gd-Y-Zn-Zr components. Repetitive thermal cycling during deposition induces solid-state transformations, notably promoting the formation of long-period stacking ordered (18R-LPSO) phases. The phases volume fractions were determined by quantitative metallography, reach a maximum of 1.43 % at a cooling time of 120 s and a minimum of 0.41 % at 45 s. Microstructural characterization reveals a characteristic bimodal grain structure comprising alternating coarse (15–35 µm) and fine (5–12 µm) equiaxed grains, with average sizes ranging from 11.32 ± 5.35 µm (180 s) to 15.62 ± 6.94 µm (45 s). Mechanical testing demonstrates strength-ductility trade-off: samples with 90 s cooling duration exhibit peak ultimate tensile strength (259.7 ± 12.7 MPa) and yield strength (224.3 ± 2.5 MPa), while 120s-cooled samples display superior elongation (8.5 ± 0.54 %) but reduced strength. These findings establish interlayer cooling time as an effective microstructural engineering tool for tailoring mechanical properties in WAAM-processed Mg-RE alloy systems through controlled thermal management.

The wire-arc directed energy deposition (WA-DED) of Mg-RE alloys is often limited by microstructural heterogeneity and unclear heat-treatment responses. In this study, the microstructural evolution and strengthening mechanisms of a WA-DED Mg-9Gd-4Y-2Zn-0.5Zr alloy during solution and aging treatments were investigated. The as-built alloy exhibited a heterogeneous α-Mg matrix containing γ′ precipitates, divorced (Mg,Zn)₃(Gd,Y) eutectic phases, and (Gd,Y)H₂ particles. Solution treatment at 450–500°C preserved the bimodal grain structure, while grain growth followed a normal grain-growth law with an apparent activation energy of ∼374.8 kJ mol⁻¹. Under sub-solvus solution treatment, the 14H-LPSO phase mainly formed through the solid-state transformation of eutectic lamellae, whereas prolonged treatment at 500°C promoted both eutectic-to-LPSO transformation and supersaturation-driven LPSO. After solution treatment at 480°C for 1 h followed by aging at 200°C for 72 h, the alloy achieved an optimized combination of strength and ductility, with yield strength, ultimate tensile strength, and elongation values of 261 MPa, 368 MPa, and 5.02%, respectively. The enhanced strength was mainly attributed to refined α-Mg grains and dense β′ precipitates.

Mg-RE alloy fabricated by directed energy deposition using electric arc (DED-Arc) has received extensive attention due to its superior mechanical performance. However, the lack of research on the special microstructure effect of high-density precipitate on the corrosion behavior limits its wider application. In this study, DED-Arc Mg-9Gd-3Y-0.5Zr (GW93K) alloys with different precipitation characteristics are obtained via different aging times, and their corrosion behavior is systematically compared with that of the solution-treated (SS) alloy. With increasing aging time, the precipitates remain β′ phase but gradually coarsen, while their number density decreases significantly after peak aging. The SS alloy exhibits the best long-term corrosion resistance due to the formation of a relatively uniform corrosion film. In contrast, the peak-aged (PA) alloy with the highest-density precipitates shows the poorest corrosion resistance, which is mainly attributed to accelerated cracking of the corrosion film. The significant grain boundary precipitation in over-aged (OA) alloys leads to the uneven distribution of corrosion products and reduced corrosion resistance. Notably, the under-aged (UA) alloy exhibits superior initial corrosion resistance compared with the SS alloy while maintaining high strength. This is attributed to the uniformly distributed high-density precipitates in the UA alloy, which promote the rapid formation of a relatively uniform and protective initial corrosion film. These findings reveal the corrosion-time-dependent effect of precipitates and provide a promising strategy for designing DED-Arc Mg-RE alloys with synergistic mechanical and corrosion performance.

Thermoelectric materials, which enable direct solid-state conversion between heat and electricity, are promising for applications in refrigeration and power generation. Bi2Te3-based thermoelectric materials have achieved commercialization due to their superior performance and mature device fabrication technology. However, the further development of Bi2Te3-based devices is hampered by the performance shortcomings of n-type compositions. Therefore, enhancing the performance of n-type Bi2Te3 is crucial for advancing practical thermoelectric technology. In this work, we collaboratively employed Se alloying at the Te site and interstitial In doping to decouple electrical transport in n-type Bi2Te3. We used a specific bond angle to evaluate the local lattice symmetry in Bi2Te3 and explained the increase in carrier mobility. First-principles calculations were also carried out to confirm the resonant level induced by In doping. Thereby, we realized the collaborative optimization of carrier mobility and effective mass to yield a high-performance n-type Bi2Te3 with a maximum thermoelectric figure of merit of similar to 1.1 at 300 K and an average ZTave of similar to 1.1 over the 300-373 K range. Furthermore, we fabricated a single-leg device based on the optimized n-type Bi2Te3 alloys and obtained a high conversion efficiency of 5.3% under a temperature difference of 225 K. This work provides a solution for improving the performance of n-type Bi2Te3 and, more importantly, proposes an indicator of the local lattice symmetry in Bi2Te3. This indicator shows promise as an effective tool for studying the relationship between local lattice symmetry and carrier mobility in Bi2Te3 and even potentially in other thermoelectric material systems.

Ti/TiO2@SiCw/Ti6Al4V composites were fabricated by selective laser melting (SLM) to investigate the influence of the Ti/TiO2@SiCw reinforcement on the microstructure of the Ti6Al4V matrix.  The results indicate that the addition of Ti/TiO2@SiCw leads to significant grain refinement, enhanced texture strength, and increased anisotropy of the Ti6Al4V matrix.   Moreover, the Ti/TiO2 dual coating protected most SiCw from degradation during the SLM process, thereby significantly improving the interfacial bonding between the reinforcement and the matrix.  This work provides an effective strategy for fabricating high-performance titanium matrix composites and offers a theoretical understanding of their microstructural evolution.KeywordsSelective laser melting;SiC-Ti6Al4V composites;Microstructure; Surface modification.

To address the limitations of traditional acoustic materials characterised by 'high absorption but low load-bearing capacity, and high load-bearing but poor absorption,' this study focuses on developing a multifunctional integrated structure that combines broadband high-efficiency sound absorption with excellent load-bearing performance. Based on additive manufacturing technology, three types of structures were designed and fabricated using sheet Diamond-TPMS as the skeleton: the pristine sheet Diamond-TPMS structure, the micro-perforated sheet Diamond-TPMS structure, and the sheet Diamond-TPMS/polyimide interpenetrating composite structure. The regulation mechanism of volume fraction on their sound absorption performance was systematically investigated. The results show that the sheet Diamond-TPMS/polyimide interpenetrating composite structure exhibits optimal comprehensive performance at a volume fraction of 20%. Its average sound absorption coefficient reaches 0.76, representing significant improvements of 55.1% and 72.7% compared to the pristine sheet Diamond-TPMS and micro-perforated sheet Diamond-TPMS structures, respectively. Moreover, it achieves efficient broadband sound absorption across the 450-6400 Hz frequency range. This performance advantage stems from the synergistic mechanism of porous dissipation and structural resonance. Ultimately, the composite structure successfully integrates acoustic and mechanical properties, achieving ultra-broadband sound absorption (relative bandwidth of 166.3%) while maintaining high load-bearing capacity, providing a reliable solution for the design of next-generation multifunctional acoustic materials.

This study prepared Al-40Sn-1Cu (wt%) alloy wires with a diameter of 1.6 mm via cold drawing (without annealing). The drawing process was conducted with a 17% similar to 21% area reduction per pass and a drawing speed of 5 mm/min. Investigating the microstructural evolution, mechanical properties, and plastic deformation mechanisms during cold drawing deformation. Results indicate that the Al-40Sn-1Cu (wt%) alloy contained Sn phases, a diffusely dispersed Al3Cu12Sn phase, a lamellar Al2Cu phase, and the Al matrix. After cold drawing, the Sn phases exhibit oriented alignment along the drawing direction (DD) with a uniform distribution. At the AlSn phase interface, stress concentration caused the Al matrix grains to refine as the primary deformation carriers. Local plastic deformation occurred in the Sn grain boundaries, ultimately forming a distinctive morphology at the phase interface that was characterized by fine Al matrix grains and concave Sn phase grain boundaries. The Al matrix develops a strong < 111 > texture and forms the high-strain layer at the interfaces between the Sn phase, Al3Cu12Sn phase, and Al matrix. During cold drawing of Al-40Sn-1Cu(wt%) alloys, the Al matrix underwent primary plastic deformation. The refined Al matrix compressed Sn grains, leading to concaved morphology formation at phase interfaces. When the cumulative area reduction reached 89%, the UTS and YS increased to 239 and 251 MPa, while the elongation decreased to 3.59%. This work demonstrates the feasibility of preparing bearing alloy wires.

This study fabricated functionally graded SiC/TiC/Ti6Al4V composites via selective laser melting (SLM) using Ti6Al4V powder and SiC whiskers. The influence of processing parameters on interfacial microstructure was systematically investigated using an orthogonal experimental design. Results indicate that as the SiC content increased from 0.25 to 1.25 wt%, the grain size gradually decreased from approximately 1.15 mu m to 1.05 mu m. The most significant grain refinement occurred at 0.75 wt% SiC, where about 62.2 % of grains were smaller than 1 mu m. This refinement is primarily attributed to in-situ formed TiC particles during SLM, which effectively pin grain boundaries and inhibit grain boundary migration. Microhardness testing indicates a peak hardness of 426 HV in the 1.25% mass fraction region, while metallurgical defects caused by compositional discontinuities at the 0.25/0.75% mass fraction interface result in a hardness reduction to 296 HV. Mechanical tests revealed that the composite's tensile strength decreased by 22.37%, accompanied by a 6.6% reduction in elongation. This decrease was primarily attributed to weakened interfacial bonding and stress concentration caused by agglomerated unreacted SiC particles. This study aims to provide theoretical foundations for the design and fabrication of highperformance gradient materials.

Laser-directed energy deposition (L-DED) was employed to fabricate Nb-15Si-22 (Ti + Zr) refractory alloys with four different combinations of Ti and Zr additions. The influence of heat treatment (1400 °C for 30 h) on their microstructure and room-temperature mechanical properties was systematically investigated. In the as-deposited state, substituting Ti with Zr promotes the transformation from metastable Nb3Si to stable γ-Nb5Si3, refines the eutectic structure, and forms a continuous Nbss+γ-Nb5Si3 network. After heat treatment, Nb3Si fully decomposes, the volume fraction of γ-Nb5Si3 increases markedly, and the dominant orientation relationship between Nbss and γ-Nb5Si3 evolves to {110} Nbss//{0001} γ, which lowers interfacial energy and enhances phase bonding. Microhardness decreases monotonically with increasing Zr content and drops further after heat treatment. Fracture toughness first increases and then decreases with Zr addition; the 14Ti8Zr alloy achieves the highest KQ of 15.1 MPa·m1/2 after heat treatment. Moderate Zr addition effectively activates multiple extrinsic toughening mechanisms- crack deflection, branching, and bridging- leading to a transition from brittle transgranular cleavage to ductile interphase tearing. This work elucidates the synergistic effects of relative amounts of Ti and Zr, and heat treatment on microstructure-property correlations in L-DED processed Nb-Si-based refractory alloys.

Wire arc additive manufacturing (WAAM) provides a viable route for fabricating large-scale rare-earth (RE) magnesium-alloy components. In WAAM, the cold metal transfer (CMT) mode strongly affects arc behavior, droplet transfer, and heat-input distribution. In this study, Mg–9Gd–4Y–1Zn–0.5Zr (wt%) alloy specimens were fabricated using four CMT-derived modes, namely, CMT, CMT Pulse (CMT-P), CMT Advanced (CMT-ADV), and CMT Pulse Advanced (CMT-PADV), and their effects on arc behavior, bead geometry, microstructure, and mechanical properties were systematically investigated. Stable deposition was achieved under all four modes, but clear differences were observed in average heat input and the within-cycle distribution of arc energy and droplet transfer. CMT exhibited relatively gentle arc action and stable short-circuit transfer, CMT-P showed the strongest arc spreading capability, and CMT-ADV and CMT-PADV displayed more pronounced expansion–contraction modulation characteristics. Polarity switching in CMT-ADV and CMT-PADV reduced the difference in eutectic-phase fraction between the fine- and coarse-grained regions. The as-deposited microstructures under all four modes were dominated by equiaxed grains and comprised similar phase constituents, predominantly including the α-Mg matrix and RE-rich secondary phases such as the (Mg,Zn)3(Gd,Y) eutectic and blocky RE-rich cubic phases. CMT, CMT-P, CMT-ADV, and CMT-PADV had average grain sizes of 22.14 ± 8.04, 17.41 ± 7.10, 16.08 ± 6.46, and 17.30 ± 7.21 μm, respectively. CMT-ADV specimens exhibited the highest tensile strength (264 ± 5 MPa), whereas CMT-PADV specimens showed the highest elongation (6.37 ± 0.52%) and weakest anisotropy. These results provide guidance for the process-mode selection and performance optimization in WAAM for RE magnesium alloys.

This study systematically investigates the effects of hot drawing speed (1.5 m/min to 3.5 m/min) on the microstructure and mechanical properties of Mg-9.5Gd-3.5Y-1Zn-0.3Zr alloy wires. Results show that a higher drawing speed intensifies the thermo-mechanical coupling effect, which uniformly fragments and disperses the long-period stacking ordered (LPSO) phase throughout the matrix. This process further refines dynamic recrystallized grains, reducing the average matrix grain size from 13.11 to 6.26 μm in the final 1.4-mm-diameter wire. Moreover, the increased speed shortens the high-temperature exposure time, keeping the wire temperature below the dissolution point of Mg5(Gd,Y)(Mg5RE) and thereby suppressing its solid solution. Consequently, the Mg5RE phase remains as a high-density dispersion in the matrix. These microstructural improvements lead to a significant increase in ultimate tensile strength (from 428 to 536 MPa) and yield strength (from 401 to 514 MPa). The strengthening mechanisms are attributed to: (1) improved distribution and aspect ratio of the LPSO phase, which inhibits grain coarsening; and (2) a strong pinning effect induced by the uniformly dispersed Mg5RE precipitates, which stabilizes the fine-grained structure and promotes the formation of high-density dislocation substructures, resulting in synergistic strengthening.

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.

This study combines density functional theory (DFT) calculations with experimental analysis. The plane-averaged charge density difference at the interfaces was systematically evaluated, and the structural evolution and electronic property changes during different stages of tensile failure were thoroughly analyzed. The experimental characterization elucidated the strengthening mechanisms of WC particles on the matrix, elemental segregation behavior, and fracture micro-morphology. The calculation results indicate that a strong polar covalent bond exists between Fe and C, and the charge redistribution at the C-terminated interface has a more profound influence. For the three WC/γ-Fe interfaces, the theoretical critical strains are 1%, 13%, and 19%, corresponding to tensile strengths of 11.98 GPa, 34.66 GPa, and 37.53 GPa, respectively. Among these, the WC(0 0 0 1)/γ-Fe(1 1 1) interface with W-HCP configuration is the highest bonding strength. A higher interfacial tensile strength tends to shift the fracture location from the interface to the interior of the matrix. Experimentally, it was found that the introduction of WC provides heterogeneous nucleation sites for the melt pool, refining the matrix microstructure. The formed tungsten-rich carbides preferentially segregate along grain boundaries, effectively impeding dislocation motion, which constitutes the primary strengthening mechanism for the enhanced plasticity of the composite.