Effect of phase decomposition on the mechanical properties of Ti-Zr-Nb-Ta-Mo multi-principal element alloys  

作　　者：Weiji Lai Xueyang Zhao Yanliang Yi Zheng Li Guodong Sun Deqiang You Wei Li Zhizhong Li Xiaojian Wang 

机构地区：[1]Guangdong Provincial Key Laboratory of Spine and Spinal Cord Reconstruction,the Fifth Affiliated Hospital(Heyuan Shenhe People’s Hospital),Jinan University,Heyuan 517000,China [2]Institute of Advanced Wear&Corrosion Resistant and Functional Materials,Jinan University,Guangzhou 510632,China [3]Jewelry Institute,Guangzhou Panyu Polytechnic,Guangzhou 511483,China [4]Shaoguan Research Institute of Jinan University,168 Muxi Avenue,Shaoguan 512029,China

出　　处：《Journal of Materials Science & Technology》2024年第32期206-221,共16页材料科学技术(英文版)

基　　金：supported by the Guangdong Basic and Applied Basic Research Foundation(Nos.2022A1515220040,2023A1515220021,and 2024A1515012353);the China Postdoctoral Science Foundation(No.2023M741370);the National Natural Sci-ence Foundation of China(No.52005217);the University Re-search Platform and Research Projects of Guangdong Education De-partment(No.2022ZDZX3003);The first-principles research is also supported by the Dongguan AIPU Technology Company Limited.

摘　　要：Body-centered cubic Ti-Zr-Nb-Ta-Mo multi-principal element alloys(MPEAs),boasting a yield strength ex-ceeding one gigapascal,emerge as promising candidates for demanding structural applications.However,their limited tensile ductility at room temperature presents a significant challenge to their processability and large-scale implementation.This study identifies phase decomposition as a critical factor influencing the plasticity of these alloys.The microscale phase decomposition in these MPEAs during solidification,driven by miscibility gaps,manifests as dendritic structures within grains.Closer examination reveals that the MPEAs with a pronounced thermodynamic propensity for phase decomposition are also suscep-tible to analogous phenomena at the atomic level.The atomic phase decomposition is characterized by the localized aggregation of some elements across nanometric domains,culminating in the establishment of short-range orderings(SROs).It is observed that phase decomposition for these MPEAs,occurring at both microscale and atomic scale,adheres to thermodynamic principles and can be predicted using the CALPHAD approach.The impact of phase decomposition on the plasticity of MPEAs fundamentally stems from the induced heterogeneities at three distinct levels:(1)Fluctuations in mechanical properties at the micron scale;(2)Variations in the strain field at the atomic scale;(3)Bond polarization and bond index fluctuations at the electronic scale.Consequently,the key to designing high-strength and high-plasticity MPEAs lies in maximizing lattice distortion while simultaneously minimizing the adverse effects of phase decomposition on the alloy’s plasticity(grain boundary cohesion).This research not only clarifies the mechanisms underpinning the ductile-to-brittle transition in high-strength Ti-Zr-Nb-Ta-Mo MPEAs but also offers crucial guidelines for developing advanced,high-performance alloys.

关 键 词：Multi-principal element alloys Phase decomposition Grain boundar FIRST-PRINCIPLES 

分 类 号：TG6[金属学及工艺—金属切削加工及机床]