反复塑性变形对SiCp／AZ31镁基复合材料组织和性能的影响

Effects of Repeated Plastic Working(RPW) on Structure and Properties of SiC_p/AZ31 Magnesium Matrix Composites

采用反复塑性变形(RPW)技术,结合挤压工艺制备出SiC颗粒增强AZ31镁基复合材料,研究了循环次数(RPW次数)对SiCp/AZ31镁基复合材料显微组织和性能的影响。结果表明,反复塑性变形具有明显的AZ31基体晶粒细化、SiCp细化和分散作用,能显著提高SiCp/AZ31复合材料的抗拉强度和硬度,并改善其塑性。在SiCp的体积分数为4%时,经RPW为300次的热挤压后,AZ31基体晶粒粒径达到最小值20μm,SiCp被粉碎成3μm以下的微粒,且弥散分布于合金基体中,复合材料的室温抗拉强度和硬度(HV)达到或接近最大值,分别为359MPa和107。

SiC particulate reinforced magnesium matrix composites SiCp/AZ31 were successfully prepared by repeated plastic working(RPW)combining with hot extrusion.Effects of cycling's times(times of RPW)on microstructure and properties of the composites were investigated.The results indicate that the RPW can refine grain sizes of AZ31 alloy and SiC particles,and uniformly distribute the SiC particle in the matrix alloy.In addition,it can not only remarkably enhance tensile strength and hardness of the composites,but also improve its plasticity.With 4% SiC particle in volumetric fraction,the ambient tensile strength and hardness of the composites can reach up to 359MPa and 107,respectively,after 300 times RPW cycling by hot extrusion,in which grain size of the matrix alloy is refined to 20 μm and SiC particles are refined to below 3 μm,dispersedly distributed in the matrix alloy.