Enhanced strength and ductility in Ti46Al4Nb1Mo alloys via boron addition

作     者：Yingmei Tan Ruirun Chen Hongze Fang Yangli Liu Hongzhi Cui Yanqing Su Jingjie Guo Hengzhi Fu Yingmei Tan;Ruirun Chen;Hongze Fang;Yangli Liu;Hongzhi Cui;Yanqing Su;Jingjie Guo;Hengzhi Fu

作者机构：National Key Laboratory for Precision Hot Processing of MetalsHarbin Institute of TechnologyHarbin 150001China School of Materials Science and EngineeringShandong University of Science and TechnologyQingdao 266590China 

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

年 卷 期：2022年第102卷第7期

页      面：16-23页

核心收录：

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

基　　金：supported by the National Natural Science Foundation of China (No. 51825401, 51971121) the China Postdoctoral Science Foundation (2019TQ0077, 2019M660071) 

主　　题：TiAl alloy TiB Microstructure Mechanical properties 

摘      要：To improve the strength and ductility of Ti Al alloys by second phase, Ti46 Al4 Nb1 Mo alloys doped with different B content(0.4%, 0.8%, 1.2%, 1.6% and 2.0%, atomic percent, hereafter in at.%, referred to as TNMx B) were prepared. Macro/microstructure evolution, mechanical properties and deformation mechanisms of the alloys were studied systematically. Results showed that the microstructure of TNM-0.4 B and TNM-0.8 B alloy remained columnar dendrites, and the secondary dendritic arms of columnar grains were more obvious. When the content of B is 1.2%, the columnar dendrites transformed to equiaxed grains, and theα2/γ lamellae colony size was further refined in TNM-1.6 B and TNM-2.0 B alloy. The morphologies and kinds of the borides were changed with increasing B content, XRD results showed that Ti B phase appeared with 1.6%B content, and both Ti B and Ti B2 phase formed in TNM-2.0 B alloy. There were straight and curved Ti B phases located around grain boundaries in TNM-0.4 B and TNM-0.8 B alloy, and when the content of B increased to 1.2%, the curved Ti B phases were reduced, while the tiny and straight Ti B phases increased. With further increasing B content to 1.6% and 2.0%, the tiny and straight Ti B phases were coarser. Compressive testing results showed that the mechanical properties of the TNM alloy were enhanced with increasing B content. The maximum strength and strain of TNM alloy were 2339 MPa and33.7% with 1.6% B addition. The compressive strength and strain were mainly enhanced via refinement of lamellar colony and formation of Ti B, and it is found that pile-up of dislocations and deformed twins promoted by Ti B are predominant in improving the mechanical properties of TNM alloys with higher strength and strain.