Processing of metastable beta titanium alloy:Comprehensive study on deformation behaviour and exceptional microstructure variation mechanisms  

作　　者：Qinyang Zhao Leandro Bolzoni Yongnan Chen Yiku Xu Rob Torrens Fei Yang 

机构地区：[1]School of Materials Science and Engineering,Chang’an University,Xi’an 710064,China [2]Waikato Centre for Advanced Materials and Manufacturing,School of Engineering,The University of Waikato,Hamilton 3240,New Zealand

出　　处：《Journal of Materials Science & Technology》2022年第31期22-43,共22页材料科学技术（英文版）

基　　金：support from National Natural Science Foundation of China(No.52101122).Q.Zhao,R.Torrens,F.Yang and L.Bolzoni would like to gratefully acknowledge the support from New Zealand Ministry of Business,Innovation and Employment(No.UOWX1402);supported by Science and Technology Major Project of Shaanxi Province(No.2020-zdzx04-01-02);Key Research Plan of Shaanxi Province(No.2021KW-18);Young Talents Promotion Project of China Association for Science and Technology(No.YESS20200335).

摘　　要：Thermomechanical processing(TMP)is especially crucial for metastableβtitanium alloys,which has received significant attention in the community for a long time.In this contribution,the processing-responding behaviour including microstructure evolution process,texture variation mechanism,and un-derlying deformation process of powder metallurgy Ti-5553 alloy in a wide processing parameter range was comprehensively investigated.Thermal physical simulation was performed on the alloy at temper-atures ranging from 800℃ to 1100℃,and strain rates between 0.001 s^(−1) and 10 s^(−1),to varied defor-mation degrees of 20%-80%height reduction.It was found that the processing parameters(i.e.temper-ature,strain rate,and deformation degree)are influential on the deformation process and resultant mi-crostructure.Varied microstructural evolution processes forβphase including flow localization,dynamic recovery,dynamic recrystallization,and grain coarsening are activated in different processing domains,while different evolution mechanisms forαphase including dynamic precipitation,phase separation,dy-namic coarsening,and mechanical shearing also play their roles under different processing conditions.In particular,four exceptional evolution mechanisms ofαprecipitation which have not been previously reported in titanium alloys were discovered and clearly demonstrated,more specifically,they are multi-interior twinning,internal compositing,layered coarsening and selective diffusion-actuated separation.After the establishment of comprehensive microstructural evolution mechanism maps,the guidance for precise processing and the knowledge reserve extension for deformation process of metastableβtita-nium alloys can be effectively achieved.

关 键 词：Metastableβtitanium alloy Powder metallurgy TMP Microstructure evolution Texture variation 

分 类 号：TG146.23[一般工业技术—材料科学与工程]