Microstructures, interface structure and room temperature tensile properties of magnesium materials reinforced by high content submicron SiCp

Abstract

The present work aims to research the treatment processing of magnesium reinforced with 1 μmsilicon carbide particle (SiCp) using stir casting combined by ultrasonic vibration. Present studies have been done on six different materials: (a) AZ31B alloy without particles, (b) 5 vol.% SiCp/AZ31B composites fabricated with different semi-solid stirring time (5 min, 10 min, 15 min and 20 min), (c) composite with 20 vol.% SiCp. The effects of 1 μm/SiCp pretreatment and stirring time on microstructure and interfacial wettability as well as mechanical properties of the materials were confirmed. Both short and long stirring time for the particle dispersion brought particle agglomeration. Results of SEM microstructure and tensile properties exhibited that the optimal stirring parameters of 625 °C/1500 rpm/15 min are exploited, and 20 vol.% SiCp/AZ31B composite was fabricated by the optimal stirring parameters. The application of optimal stirring parameters for the treatment resulted in homogeneous particle distribution. The addition of SiCp leads to a reduced matrix grain, and 20 vol.% SiCp/AZ31B composite showed smaller grain size than. 5 vol.% SiCp/AZ31B composite. The interface between SiCp and matrix is clear and interfacial wettability well. Tensile test results show that with increasing SiCp content, strengths increase while ductility decreases.

Keywords

• magnesium matrix composites
• microstructure
• interfacial wettability
• tensile strengths