Martensite decomposition under thermal-mechanical coupling conditions to fabricate an ultrafine-grained Ti6Al4Mo4Zr1W0.2Si alloy  

作　　者：Taoyu Zhou Jiuxu Yang Nan Li Hao Sun Bohua Zhang Zibo Zhao Qingjiang Wang 

机构地区：[1]Shi-changxu Innovation Center for Advanced Materials,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China [2]School of Materials Science and Engineering,University of Science and Technology of China,Shenyang 110016,China

出　　处：《Journal of Materials Science & Technology》2024年第1期157-168,共12页材料科学技术（英文版）

基　　金：supported by the Youth Innovation Promotion Association CAS(No.2020193);CAS Project for Young Scientists in Basic Research(No.YSBR-025);National Science and Technol-ogy Major Project(No.J2019-VI-0005-0119).

摘　　要：The fabrication of ultrafine-grained microstructures(grain size below 1μm)in titanium alloys is beneficial for improving their mechanical properties at room temperature and medium tempera-tures(400-550°C).However,a long-standing challenge involves the low-cost manufacturing of bulk ultrafine-grained titanium alloys.In this work,we developed a facile strategy through martensite de-composition at thermal-mechanical coupling conditions,to fabricate an equiaxed microstructure in a Ti6Al4Mo4Zr1W0.2Si model alloy with an averageαgrain size of 315±62 nm.The formation of the ultrafine-grained microstructure was because the lattice strain stored in the martensitic initial mi-crostructure enhanced the nucleation rate of dynamic recrystallization,meanwhile,the pinning role of martensite decomposition productsβand(Ti,Zr)_(5)Si_(3)phases suppressed grain coarsening at high tem-peratures.Compared to conventional(α+β)alloys,the tensile strength of this alloy improved by 20%-30%at both room temperature and 550°C,without decreasing its ductility.In situ SEM observations revealed that the ultrafine-grained microstructure would not only suppress dislocation motions but also contribute to the homogenous deformation in the matrix of the material,therefore,it resulted in higher mechanical performance.The research results may be of great significance to the development of next-generation aviation titanium alloys.

关 键 词：ULTRAFINE-GRAINED Titanium alloy In situ observation Deformation mechanism Thermostability 

分 类 号：TG1[金属学及工艺—金属学]