中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 31 No. 8 August 2021 |
（1. School of Mechanical Engineering, Guizhou University, Guiyang 550025, China;
2. School of Mechanical Engineering, Dongguan University of Technology, Dongguan 523808, China;
3. School of Mechanical and Automotive Engineering, South China University of Technology, Guangzhou 510640, China;
4. Department of Applied Science, University of Quebec at Chicoutimi, Quebec, Canada）
Abstract:The differences in the microstructure and elevated temperature tensile properties of gravity die cast, squeeze cast, and semi-solid thixoformed Al-Si-Cu-Mn-Fe alloys after thermal exposure at 300 °C were discussed. The results demonstrate that the elevated temperature tensile properties of semi-solid thixoformed alloys were significantly higher than those of gravity die cast and squeeze cast alloys, especially after thermal exposure for 100 h. The ultimate tensile strength (UTS) of semi-solid thixoformed alloys after thermal exposure at 300 °C for 0.5, 10 and 100 h were 181, 122 and 110 MPa, respectively. The UTS values of semi-solid thixoformed alloys were higher than those of heat resistant aluminum alloys used in commercial applications. The enhanced elevated temperature tensile properties of semi-solid thixoformed experimental alloys after thermal exposure can be attributed to the combined reinforcement of precipitation strengthening and grain boundary strengthening due to thermally stable intermetallic phases as well as suitable grain size.
Key words: Al-Si alloys; iron-rich intermetallics; semi-solid thixoforming; microstructure; tensile properties; thermal exposure
