包套热挤压SiCp/6066铝基复合材料断裂机制和强化机制的研究

采用包套热挤压工艺制备了不同体积分数SiC颗粒增强的6066铝基复合材料,结合其断口形貌及微观组织,分析了材料的断裂机制及抗拉强度和屈服强度随SiC增强颗粒体积分数变化的规律.结果表明,材料的断裂机制为颗粒与基体间的界面脱粘以及SiC团聚体的脆性开裂.当SiC颗粒的体积分数小于12%时,随着SiC颗粒增强相的增加,SiCp/6066铝基复合材料的抗拉强度和屈服强度增加.当SiC颗粒的体积分数大于12%时,材料的强度增加减缓或略有下降,其主要强化机制是位错强化和弥散强化.

Research on Fracture and Strengthening Mechanisms of SiCp/6066 Aluminum Matrix Composites with Canned Hot Extrusion

The composites reinforced by silicon carbide(SiC) particulate with various volumes fraction are fabricated by canned hot extrusion. The fracture and strengthening mechanism are studied by micrographs of tensile fracture surface and microstructure of the composites. The results suggest that this composite fracture mechanism is disengagement of the interface and brittle cleavage of the SiC aggregate, and the ultimate tensile strength and 0.2% offset yield strength increase with the increase of SiC reinforcement volumes fraction when this fraction is below 12%.When SiC reinforcement volumes fraction is above 12%,the composite strength increases slowly or decreases. The main strengthening mechanisms are dislocation and dispersion strengthening.