Development of Ti-Al-Ta-Nb-(Re)near-αhigh temperature titanium alloy:Microstructure,thermal stability and mechanical properties

作     者：Juan Li Yaqun Xu Wenlong Xiao Chaoli Ma Xu Huang Juan Li;Yaqun Xu;Wenlong Xiao;Chaoli Ma;Xu Huang

作者机构：Key Laboratory of Aerospace Advanced Materials and Performance of Ministry of EducationSchool of Materials Science and EngineeringBeihang UniversityBeijing 100191China AECC Beijing Institute Of Aeronautical MaterialsBeijing 100095China 

出 版 物：《Journal of Materials Science & Technology》 (材料科学技术（英文版）)

年 卷 期：2022年第109卷第14期

页      面：1-11页

核心收录：

学科分类：08[工学] 0806[工学-冶金工程] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 

基　　金：financially support by National Key Research and Development Program of China(No.2017YFB0306205) National Natural Science Foundation of China(NSFC,No.51671012) the Fundamental Research Funds for the Central Universities International Science and Technology Cooperation Program of China(2015DFA51430)。 

主　　题：Titanium alloy High temperature Microstructure Mechanical properties α_(2)precipitates Thermal exposure 

摘      要：Mechanical properties and microstructural stability under the service temperature are important to the high temperature titanium alloy.In order to evaluate the potential in increase the service temperature of Ti alloy,two near-αTi alloys with high content of Al asα-stabilizer and Ta,Nb and/or Re asβ-stabilizers were designed and prepared by ingot metallurgy and thermomechanical processing,and the microstructure and mechanical properties before and after thermal exposure at 650℃ for 100 h were characterized.The results indicated that due to the weakβ-stabilizing ability of Ta and Nb elements,only a small amount ofβphase was formed in Ti-10Al-4Ta-2Nb alloy.With a trace Re addition,theβphase was obviously increased in Ti-10Al-4Ta-2Nb-0.25Re,indicating that the Re was a strongβ-stabilizer.Under the same thermomechanical conditions,the Re addition decreased the volume fraction of primaryα(α_(p))phase and refined the secondaryα(α_(s))phase evidently.The primaryαphase presented an obvious core-shell structure in the Ti-10Al-4Ta-2Nb alloy,with higher Al concentration in the shell.While the core-shell structure was not obvious in the Re-containing alloy due to the Re decreases the diffusion of Al,Ta and Nb elements.A large number of orderedα_(2)precipitates can be observed in theα_(p)andα_(s) phases of two alloys.Theα_(2)precipitates continuously grew up during thermal exposure,however,their growth rate in theα_(s)phase of Re-containing alloy were lower than that of Ti-10Al-4Ta-2Nb alloy.Although plenty of orderedα_(2)precipitates formed in the Ti-10Al-4Ta-2Nb alloy,the alloy had a certain plasticity at room temperature.The trace Re addition evidently increased the tensile strength but caused the decrease of the plasticity.After thermal exposure,the strength was further increased,while the plasticity was decreased for both of alloys.