中國有色金屬學報(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 34 No. 11 November 2024 |
（1. State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China;
2. CITIC Dicastal Co., Ltd., Qinhuangdao 066004, China;
3. College of Materials Science and Engineering, Yanshan University, Qinhuangdao 066004, China;
4. Capital Aerospace Machinery Co., Ltd., Beijing 100076, China）
Abstract:The microstructures and hot tensile behaviors of ZK30 alloys subjected to single- and multi-pass friction stir processing (FSP) were systematically investigated. Following single-pass FSP (S-FSP), coarse grains underwent refinement to 1-2 μm, with a distinct basal texture emerging in the stir zone (SZ). Additionally, second-phase particles were fragmented, dispersed, and partially dissolved. Multi-pass FSP (M-FSP) further enhanced the homogeneity of the microstructure, reduced texture intensity differences, and decreased the fraction of second-phase particles by 50%. Both S-FSP and M-FSP SZs demonstrated superplasticity at strain rates below 1×10-3 s-1 and at temperatures of 250-350 °C. The S-FSP SZ exhibited an elongation of 390% at 250 °C and 1×10-4 s-1, while the M-FSP SZ achieved an elongation of 406% at 350 °C and 1×10-3 s-1. The superplastic deformation of SZ was co-dominated by grain boundary sliding (GBS) and the solute-drag mechanism in S-FSP and mainly by GBS in M-FSP.
Key words: ZK30 alloys; multi-pass friction stir processing; superplasticity; microstructure; hot tensile behavior
