中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 23 No. 12 December 2013 |
（1. AVIC Beijing Aeronautical Manufacturing Technology Research Institute, Beijing 100024, China;
2. School of Materials Science and Engineering, University of Science and Technology Beijing,
Beijing 100083, China）
Abstract:A detailed investigation for the influence of post weld heat treatment (PWHT) on the microstructure of TC4 and TC17 dissimilar joints was analyzed. The fully transformed microstructure in the as-welded zone indicated that the peak temperature exceeded the β-transus temperature at the weld interface during linear friction welding. TC4 side was mainly composed of martensite α′ phase with random distribution and it was single β for that of TC17. In the thermomechanically affected zones of TC4 and TC17, the structure undergoes severe plastic deformation and re-orientation, yet without altering the phase fractions. After PWHT, in the weld zone of TC4 alloy, the phase transformation α′→ α+β occurred and the acicular α was coarsened, which resulted in a decrease in hardness. In the weld zone of TC17 alloy, fine α phase precipitated at the grain boundary and within β grains, which resulted in a sharp increase in hardness.
Key words: linear friction welding; Ti alloys; heat treatments; microstructure; microhardness
