中國有色金屬學報(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 30 No. 4 April 2020 |
（1. Department of Mining and Metallurgy, Amirkabir University of Technology, Tehran, Iran;
2. Faculty of Engineering, University of Kashan, Kashan, Iran;
3. Department of Materials Science and Engineering, Sharif University of Technology, Tehran, Iran;
4. Institute of Materials Engineering and Advanced Processes, Department of Mining and Metallurgy, Amirkabir University of Technology, Tehran, Iran）
Abstract:An improved method of friction stir processing (FSP) was introduced for the processing of AZ91 magnesium alloy specimens. This novel process was called “friction stir vibration processing (FSVP)”. FSP and FSVP were utilized to develop surface composites on the studied alloy while SiC nanoparticles were applied as second-phase particles. The effect of reinforcing SiC particles with different sizes (30 and 300 nm) on different characteristics of the composite surface was studied. The results indicated that the microstructure was refined and mechanical properties such as hardness, ductility, and strength were enhanced as FSVP was applied. Furthermore, it was concluded that the effect of reinforcing particles with a size of 30 nm on the microstructure and mechanical properties of the surface composite was more obvious than that of particles with a size of 300 nm. It was also found that mechanical properties and microstructure of FSV-processed specimens were improved as vibration frequency increased. The hardness value in the stir zone was about 157 MPa for the FSV-processed specimen at a vibration frequency of 50 Hz, while this value was around 116 MPa for the FSV-processed specimen at a vibration frequency of 25 Hz.
Key words: friction stir processing; vibration; SiC nano-particles; particle size; mechanical properties; microstructure; residual stress
