Heterogeneous precipitate microstructure in titanium alloys for simultaneous improvement of strength and ductility  

作　　者：Mengyuan Hao Pei Li Xuexiong Li Tianlong Zhang Dong Wang Qiaoyan Sun Libin Liu Jinshan Li Yuyou Cui Rui Yang Dongsheng Xu 

机构地区：[1]Frontier Institute of Science and Technology,State Key Laboratory for Mechanical Behavior of Materials,Xi’an Jiaotong University,Xi’an 710049,China [2]Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China [3]School of Materials Science and Engineering,Central South University,Changsha 410083,China [4]State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi’an 710072,China [5]Thermal Power Research Institute Co.Ltd.,Xi’an 710032,China

出　　处：《Journal of Materials Science & Technology》2022年第29期150-163,共14页材料科学技术（英文版）

基　　金：the National Key Research and Development Program of China(No.2016YFB0701302);the National Natural Science Foundation of China(Nos.52171012 and 51931004);“H2”High-Performance Cluster,the internal City University of Hong Kong under the Programs 7004894 and 9380060。

摘　　要：The design of alloys with simultaneous high strength and high ductility is still a difficult challenge.Here,we propose a new approach to designing multi-phase alloys with a synergistic combination of strength and ductility by engineering heterogeneous precipitate microstructures through the activation of different transformation mechanisms.Using a two-phase titanium alloy as an example,phase field simulations are carried out firstly to design heat treatment schedules that involve both conventional nucleation and growth and non-conventional pseudospinodal decomposition mechanisms,and the calculated microstructures have been evaluated by crystal plasticity finite element modeling.According to simulations,we then set a two-step heat treatment to produce bimodalα+βmicrostructure in Ti-10V-2Fe-3Al.Further mechanical testing shows that the ductility of the alloy is increased by~50%and the strength is increased by~10%as compared to its unimodal counterpart.Our work may provide a general way to improve the mechanical properties of alloys through multiscale microstructure design.

关 键 词：Titanium alloys Phase field simulation Crystal plasticity finite element Two-step aging Pseudospinodal decomposition mechanisms Multiscale heterogeneous microstructure 

分 类 号：TG146.23[一般工业技术—材料科学与工程]