The effects of ultrasonic power

ultrasonic treatment time and temperature on properties of insitu Mg2Si/AZ91 composites were investigated

and orthogonal experiment was designed to optimize process.The results reveal that ultrasonic treatment can refine obviously as-cast microstructure of the composites

and the morphology of primary Mg2 Si phases is converted from chunk to fine particle

and a little eutecticβ-Mg17 Al12 phase is precipitated with dis-continuous net-like structure.The tensile strength and elongation of the composite exhibit desirable when the ultrasonic treatment temperature is690 ℃and ultrasonic power is 700 Was well as ultrasonic treatment for 65 s.The tensile strength is increased from 167 MPa to 209 MPa

and the elongation is increased form 1.8%to 3.3% after ultrasonic treatment

increased by 25% and 89%

respectively.