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

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

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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.

Multi-principal element alloysPhase decompositionGrain boundarFirst-principles

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

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Guangdong Provincial Key Laboratory of Spine and Spinal Cord Reconstruction,the Fifth Affiliated Hospital(Heyuan Shenhe People's Hospital),Jinan University,Heyuan 517000,China

Institute of Advanced Wear & Corrosion Resistant and Functional Materials,Jinan University,Guangzhou 510632,China

Jewelry Institute,Guangzhou Panyu Polytechnic,Guangzhou 511483,China

Shaoguan Research Institute of Jinan University,168 Muxi Avenue,Shaoguan 512029,China

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2024

10.1016/j.jmst.2024.01.088

材料科学技术(英文版)
中国金属学会 中国材料研究学会 中国科学院金属研究所

材料科学技术(英文版)

CSTPCD
影响因子：0.657
ISSN：1005-0302
年,卷(期)：2024.199(32)