往复镦挤对SiC_p/2024铝基复合材料组织性能的影响

采用室温拉伸测试、扫描电镜及透射电镜等手段研究了往复镦挤变形工艺对SiCp/2024铝基复合材料显微组织和力学性能的影响.结果表明,SiCp/2024铝基复合材料经过往复墩挤后,基体组织出现细化,SiC颗粒发生破碎,基体中SiC颗粒由团聚变得分布均匀;在交替剪切变形作用下,基体中的位错发生重组和湮灭,形成细小的亚晶;相对于挤压态,经过4道次变形后,复合材料抗拉强度由271 MPa提高到378 MPa,屈服强度由203MPa提高到260 MPa;经过往复镦挤变形后,拉伸断口以界面脱粘和颗粒断裂方式为主.

Microstructures and Mechanical Properties of SiCp/2024 Aluminum Matrix Composites by Repetitive Upsetting and Extrusion

The microstructures and mechanical properties of SiCp/2024 composite processed by repetitive upsetting and extrusion (RUE) were investigated through tensile testing, optional microscopy(OM),scanning election microscopy(SEM) and transmission election microscopy(TEM). The results showed that the matrix was effectively refined during the repetitive deformation, the distribution of SiC particles was improved, and some SiC particles were broken by shear force. Due to alternating shear deformation, the dislocation on the matrix was reorganized and annihilated, and then some small sub-grains were formed. Compared with the as-extruded SiCp/2024 composite, the tensile strength increased from 271 MPa to 378 MPa after 4 passes, and the yield strength increased from 203 MPa to 260 MPa. The fracture of the composite after RUE mainly resulted from interfacial debonding and SiC particles breakage.