表面技术2025，Vol.54Issue(16)：39-59,21.DOI:10.16490/j.cnki.issn.1001-3660.2025.16.003
选择性激光熔化制备难熔高熵合金研究进展
Research Progress on Selective Laser Melting of Refractory High-entropy Alloys
摘要
Abstract
Refractory high-entropy alloys(RHEAs),composed of multiple principal elements with high melting points,have garnered significant attention for their exceptional mechanical strength,oxidation resistance,and thermal stability,making them ideal candidates for extreme-environment applications in aerospace,nuclear energy,and biomedical engineering.Currently,conventional RHEA preparation processes such as arc melting,powder metallurgy and magnetron sputtering have certain limitations in practical applications.Specifically,arc melting is limited by a low cooling rate(100-102 K/s),which is prone to inducing macroscopic segregation,coarse grains(grain size>100 μm)and shrinkage defects.While powder metallurgy can achieve compositional homogeneity through mechanical alloying,the long-time high-temperature holding time of the conventional sintering process triggers abnormal coarsening of brittle intermetallic compounds(e.g.,σ-phase,Laves-phase).Magnetron sputtering,as a physical vapour-phase deposition technique,can prepare nano-crystalline/amorphous structures with a homogeneous distribution of compositions,but it is difficult to obtain direct access to the nanocrystalline/amorphous structure due to the low deposition rate and the finite forming dimensions.Selective laser melting(SLM),an advanced additive manufacturing technique,addresses these challenges through ultrahigh cooling rates(103-105 K/s)and precise layer-by-layer fabrication,enabling unprecedented control over microstructural refinement and property enhancement.The work aims to comprehensively examine recent advancements in SLM-processed RHEAs,focusing on process-microstructure-property relationships,defect mitigation strategies,and industrial applications,while identifying critical challenges and future research directions. Key findings highlight that SLM achieves remarkable grain refinement,reducing average grain sizes from>200 μm in cast alloys to<20 μm,with further reductions to 10.6 μm through microalloying(e.g.,0.5at.%C in NbMoTaW).Energy density,governed by laser power,scan speed,and layer thickness,critically affects relative density and porosity.Advanced characterization via EBSD and TEM reveals metastable phase formation and in-situ nano-precipitates(e.g.,NbC,TiC),which enhances mechanical properties through grain boundary pinning and dislocation interaction.For instance,SLM-fabricated VNbMoTaW alloys exhibit compressive strengths of 993.84 MPa at 1 000℃,retaining 62.2%of their room-temperature strength,while NbMoTaW-0.5C demonstrates a 43.3%increase in yield strength(1 391 MPa)and improved ductility(6.9%strain). The rapid solidification inherent to SLM suppresses elemental segregation,promoting homogeneous microstructures and dense oxide layers(e.g.,Nb2O5,Ta2O5)that enhance corrosion resistance.Electrochemical tests reveal corrosion current densities as low as 8.716×10-11 A/cm² for SLM-processed NbMoTaW in 3.5%NaCl,surpassing 316L stainless steel.High-temperature oxidation resistance is further bolstered by ternary oxides(e.g.,Ta16W18O94)formed at elevated energy densities(>150 J/mm³),effectively inhibiting oxygen diffusion.Biomedical applications leverage SLM's design flexibility to fabricate porous TiNbTaZrMo implants with tunable Young's modulus(6.71-16.21 GPa),mimicking bone trabeculae to mitigate stress shielding.Osteoblast adhesion and actin filament development on these alloys rival pure titanium,underscoring their biocompatibility. Despite these advancements,SLM-processed RHEAs face challenges including residual stress(up to 380 MPa at 400 mm/s scan speed),microcracks,and compositional heterogeneity.Residual stress is mitigated by optimizing scan strategies(e.g.,stripe vs.chessboard patterns)and post-processing techniques like hot isostatic pressing(HIP),which reduces porosity by 60%.Crack initiation is suppressed through compositional adjustments(e.g.,1at.%C additions to limit oxygen segregation)and adaptive parameter tuning.For example,lowering scan speeds to 600 mm/s reduces surface roughness and transforms long cracks into isolated micropores. Industrial applications demonstrate SLM's capability to produce complex geometries such as turbine blades,lattice structures,and gradient components.Case studies include lightweight WNbMoTa turbine blades with high strength-to-weight ratios and Ta-rich RHEAs for nuclear reactor cladding,capitalizing on their irradiation resistance.Future research must prioritize defect control through in-situ monitoring,compositional uniformity via machine learning-driven alloy design,and performance validation under extreme conditions(e.g.,>1 200℃oxidation,neutron irradiation).Multi-scale simulations(phase-field and molecular dynamics)are essential to decode melt pool dynamics,while hybrid processes(e.g.,laser remelting)could enhance surface functionality. In conclusion,SLM represents a transformative approach to RHEA manufacturing,offering unmatched microstructural control and performance optimization.By bridging laboratory innovation and industrial demands,this technology unlocks new possibilities for high-performance materials in extreme environments.Collaborative efforts in process refinement,computational modeling,and interdisciplinary integration will be pivotal to advancing SLM-processed RHEAs toward widespread commercialization.关键词
选择性激光熔化/耐火高熵合金/微观结构演化/力学性能/增材制造Key words
selective laser melting/refractory high-entropy alloys/microstructural evolution/mechanical properties/additive manufacturing分类
矿业与冶金引用本文复制引用
朱恩,杨宝震,张登科,张微,李婉秋,虞飞标..选择性激光熔化制备难熔高熵合金研究进展[J].表面技术,2025,54(16):39-59,21.基金项目
新疆维吾尔自治区自然科学基金(2023D01C193) （2023D01C193）
新疆大学2025优秀研究生创新项目(XJDX2025YJS203)Natural Science Foundation of Xinjiang Uygur Autonomous Region(2023D01C193) （XJDX2025YJS203）
Xinjiang University 2025 Outstanding Graduate Student Innovation Program(XJDX2025YJS203) （XJDX2025YJS203）
