超声处理原位自生Mg_2Si/AZ91复合材料的工艺优化

Optimum Design of Ultrasonic Treatment of In-Situ Mg_2Si/AZ91 Composites

研究了超声功率、超声处理时间和超声处理温度对原位自生Mg2Si/AZ91复合材料性能的影响,并设计正交试验优化工艺。结果表明,超声处理后的复合材料铸态组织中,基体晶粒细化明显,初生Mg2Si相由粗大块状转变为近球状,共晶β-Mg17Al12相析出较少,并呈断网状。当超声处理温度为690℃、超声功率为700 W、超声处理为65s时,复合材料的抗拉强度和伸长率最佳,抗拉强度由未超声处理时的167 MPa提高至209 MPa,伸长率由未超声处理时的1.8%提升至超声处理后的3.4%,分别提升了25%和89%。

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.