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采用搅拌铸造法成功制备了SiC_P/Mg(AZ91)复合材料并对铸态复合材料进行了等通道角挤压变形(Equal channel angular pressing,ECAP)。结果表明,搅拌铸造态SiC_P/AZ91复合材料的基体组织致密,颗粒与基体结合良好,没有出现宏观团聚;SiC_P大部分聚集在晶界附近区域并呈“项链状”分布。ECAP变形可以有效地消除铸态SiC_P/AZ91复合材料中的SiC_P“项链状”分布,并且随着ECAP道次的增加,SiC_P分布更加均匀;在ECAP过程中,SiC_P发生了一定断裂但并不明显。SiC_P/AZ91复合材料基体晶粒随着变形道次的提高而逐渐细化。基体晶粒细化以及SiC_P分布均匀化是SiC_P/AZ91复合材料屈服强度和抗拉强度随着道次提升而逐渐增加的主要原因。
The SiC_P / Mg (AZ91) composites were successfully prepared by means of stirring casting and the ECAP was performed on the as-cast composites. The results show that the microstructure of the SiC_P / AZ91 composite is compact and the matrix is well bonded with the matrix. There is no macroscopic agglomeration. Most of the SiC_P aggregates in the vicinity of the grain boundaries and presents a “necklace” distribution. ECAP deformation can effectively eliminate the SiC_P “necklace ” distribution in the as-cast SiC_P / AZ91 composites, and the distribution of SiC_P becomes more uniform with the increase of the ECAP pass. In the ECAP process, SiC_P undergoes some fracture but Not obvious. SiC_P / AZ91 composites matrix grains gradually refine with the increase of deformation pass. The grain refinement of matrix and homogenization of SiC_P are the main reasons for the increase of yield strength and tensile strength of SiC_P / AZ91 composites with the increase of pass.