物理学报2025，Vol.74Issue(8)：168-177,10.DOI:10.7498/aps.74.20250141
(NiCoV)95W5中熵合金的动态力学性能与变形机理
Dynamic mechanical properties and deformation mechanism of(NiCoV)95W5 medium entropy alloy
摘要
Abstract
Medium-entropy alloys(MEAs),renowned for their outstanding strength and ductility,possess great potential for high strain-rate applications.This study focuses on a NiCoV-based MEA system,and proposes a novel alloy design strategy to fabricate the(NiCoV)95W5 alloy by introducing 5％(atomic percent)high-melting-point tungsten through vacuum arc melting coupled with thermomechanical processing.Split Hopkinson pressure bar(SHPB)experiments are conducted to elucidate the dynamic response mechanism and deformation behavior under high strain rates(2000-6000 s-1).The results show that due to severe lattice distortion,the enhanced phonon drag effect at elevated strain rates results in a substantial increase in yield strength from 720 MPa(10-3 s-1)to 1887 MPa(6000 s-1),an increase of 162％,accompanied by a relatively high strain-rate sensitivity(m=0.42).Microscopic analysis reveals the multi-scale cooperative deformation mechanism of the alloy system under high strain rate.When the strain rate is 2000 s-1,the alloy exhibits a low dislocation density dominated by dislocation planar slip.As the strain rate increases to 4000 s-1,the increased flow stress and deformation promote the proliferation and entanglement of a large number of dislocations into high-density dislocation cells.The accumulation of dislocation stress leads to the coordinated deformation of precipitates and releases stress concentration at the phase interface.When the strain rate further increases to 6000-1,severe plastic deformation will lead to the formation of nanotwins within the matrix,which is the main strain hardening.This study elucidates the dynamic response mechanism of NiCoV MEA mediated by tungsten doping,providing a guidance for designing novel structural materials with excellent dynamic mechanical responses.关键词
中熵合金/动态压缩变形/加工硬化/析出强化Key words
medium-entropy alloy/dynamic compression deformation/work hardening/precipitation strengthening引用本文复制引用
路圣晗,陈颂阳,崔广鹏,周丹,蔡伟金,宋旼,王章维..(NiCoV)95W5中熵合金的动态力学性能与变形机理[J].物理学报,2025,74(8):168-177,10.基金项目
国家自然科学基金(批准号:52471153)、中南大学中央高校基本科研业务费(批准号:2024ZZTS0688,2024ZZTS0408)和湖南省自然科学基金青年学生基础研究项目(批准号:2024JJ10011)资助的课题. Project supported by the National Natural Science Foundation of China(Grant No.52471153),the Fundamental Research Funds for the Central Universities,Central South University,China(Grant Nos.2024ZZTS0688,2024ZZTS0408),and the Basic Research Program for Young Students of Natural Science Foundation of Hunan Province,China(Grant No.2024JJ10011). （批准号:52471153）
