中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 24 No. 10 October 2014 |
（1. School of Materials Science and Engineering, Dalian University of Technology, Dalian 116085, China;
2. State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China;
3. Key Laboratory of Materials Modification of Ministry of Education,
Dalian University of Technology, Dalian 116085, China）
Abstract:Direct friction welding of TiAl alloy to 40Cr steel rods was conducted, and the microstructure and mechanical properties of the resultant joints in as-welded and post-weld heat treatment (PWHT) states were investigated. The martensitic transformation occurred and brittle TiC phase formed near the interface due to C agglomeration, which degraded the joint strength and increased the microhardness at the interface in as-welded state. Feathery and Widmanstatten structure generated near the interface on TiAl alloy side. After PWHT at 580 °C and 630 °C for 2 h, the sorbite formed and C dispersed at the interface, leading to the increase of the joint strength from 86 MPa in as-welded state to 395 MPa and 330 MPa, respectively. The heat-treated specimen fractured with quasi-cleavage features through the zone 1 mm away from the interface on TiAl alloy side, but the as-welded specimen failed through the interface.
Key words: TiAl alloy; steel; dissimilar metal joining; friction welding; post-weld heat treatment
