Microstructure Characteristics and Elevated Temperature Mechanical Properties of a B Containedβ-solidifiedγ-TiAl Alloy  

作　　者：王秀琦 GUO Ruiqi 刘国怀 LI Tianrui YANG Yuxuan CHEN Yang XIN Meiling WANG Zhaodong WANG Xiuqi;GUO Ruiqi;LIU Guohuai;LI Tianrui;YANG Yuxuan;CHEN Yang;XIN Meiling;WANG Zhaodong(State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,China;School of Materials Science and Engineering,Harbin Institute of Technology at Shenzhen,Shenzhen 518055,China;School of Metallurgical Engineering,Anhui University of Technology,Maanshan 243000,China)

机构地区：[1]State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,China [2]School of Materials Science and Engineering,Harbin Institute of Technology at Shenzhen,Shenzhen 518055,China [3]School of Metallurgical Engineering,Anhui University of Technology,Maanshan 243000,China

出　　处：《Journal of Wuhan University of Technology(Materials Science)》2024年第3期738-746,共9页武汉理工大学学报（材料科学英文版）

基　　金：Funded by the National Natural Science Foundation of China(No.52071065);Fundamental Research Funds for the Central Universities(No.N2007007)。

摘　　要：The improved microstructure and enhanced elevated temperature mechanical properties of Ti-44Al-5Nb-(Mo,V,B)alloys were obtained by vacuum arc re-melting(VAR)and primary annealing heat treatment(HT)of 1260℃/6 h/Furnace cooling(FC).The phase transformation,microstructure evolution and tensile properties for as-cast and HTed alloys were investigated.Results indicate that three main phase transformation points are determined,T_(eut)=1164.3℃,T_(γsolv)=1268.3℃and T_(βtrans)=1382.8℃.There are coarse lamellar colonies(300μm in length)and neighbor reticular B2 andγgrain(3-5μm)in as-cast alloy,while lamellar colonies are markedly refined and multi-oriented(20-50μm)as well as the volume fraction and grain sizes of equiaxedγand B2 phases(about 15μm)significantly increase in as-HTed alloy.Phase transformations involvingα+γ→α+γ+β/B2 and discontinuousγcoarsening contribute to the above characteristics.Borides(1-3μm)act as nucleation sites forβ_(eutectic) and produce massiveβgrains with different orientations,thus effectively refining the lamellar colonies and forming homogeneous multi-phase microstructure.Tensile curves show both the alloys exhibit suitable performance at 800℃.As-cast alloy shows a higher ultimate tensile stress of 647 MPa,while a better total elongation of more than 41%is obtained for as-HTed alloy.The mechanical properties improvement is mainly attributed to fine,multi-oriented lamellar colonies,coordinated deformation of homogeneous multi-phase microstructure and borides within lamellar interface preventing crack propagation.

关 键 词：TiAl alloy phase transformation heat treatment BORIDE microstructure mechanical properties 

分 类 号：TG146.23[一般工业技术—材料科学与工程]