Effect of Ageing Treatment on SiC_p/AZ61 Composite Microstructure and Mechanical Properties
The ageing treatment of SiCp/AZ61 magnesium matrix composite fabricated by ultrasonic stirring was studied.The results show that the secondary precipitation phase during ageing is Mg17Al12,and the secondary phase is precipitated in continuous and discontinious precipitation ways.Compared with AZ61 magnesium alloy,the incubation period of its ageing is longer,and the microhardness decreases slowly during over-aging.The microhardness of SiCp/AZ61 magnesium matrix composite is 66.5 HB after solution treatment at 420 ℃ for 10 h.The highest microhardness of 81.5 HB can be obtained after ageing at 250 ℃ for 10 h. Compared with AZ61 magnesium alloy,the microhardness increases by 54%.