高能超声对Mg2 Si / AZ91D 复合材料的影响

为改善原位颗粒增强镁基复合材料的性能,采用原位合成技术制备了Mg2Si/AZ91D复合材料,通过在熔体中施加高能超声,研究了超声时间和超声功率对复合材料组织性能的影响.结果表明:随着超声时间的延长或超声功率的增大,复合材料中粗大的汉字状Mg2Si相变得细小、分布均匀,同时细小分布均匀的球化状β-Mg17Al12相增多;超声时间为6 min、超声功率为1.2 kW时,组织中呈短棒状的Mg2Si颗粒和球化状β-Mg17Al12相分布均匀,且复合材料的抗拉强度和伸长率达到最大,分别为220.5 MPa和2.6%,较未施加超声的复合材料试样提高了22.3%和38.9%;再延长处理时间或增大输出功率,组织有粗化的趋势,复合材料的抗拉性能及伸长率也呈现先升后降趋势.

Influence of high-energy ultrasonic treatment on Mg2 Si / AZ91D composites

To improve the mechanical properties of in situ particle reinforced magnesium matrix composites,the influence of ultrasonic time and power on the microstructure and properties of in-situ Mg2Si/AZ91D composites by introducing high-energy ultrasonic into the melt were investigated.The results indicate that the morphology of Mg2Si phase transforms from the coarser into finer and distributes uniformly with increasing the ultrasonic treatment time or ultrasonic output power.Meanwhile,the number of finer uniform spherical β-Mg17Al12 phase is increased.The best ultrasonic effects are obtained as the power is 1.2 kW and the time is 6min,there exist the well-distributed cosh shape Mg2Si phase and spherical β-Mg17Al12 phase.The tensile strength and the elongation reach 220.5 MPa and 2.6%,increased by 22.3% and 38.9% than those without ultrasonic assistance,respectively.Further prolonging time and increasing output power will make the microstructure coarse,and the tensile strength and elongation of the composite increase first and then decrease.