亚微米级SiC颗粒增强铝基复合材料的拉伸性能与强化机制

TENSILE PROPERTIES AND STRENGTHENING MECHANISMS OF PURE ALUMINUM MATRIX COMPOSITE REINFORCED WITH SUB- MICROMETRIC SiC PARTICLES

用粉末冶金法制备了亚微米SiC颗粒增强纯铝基复合材料(Al MMC),对该材料的微观结构和拉伸性能进行了研究.结果表明,15％SiCp(150 nm)/Al MMC的拉伸强度和屈服强度分别为342.3和272.4 MPa,比纯铝分别提高了89.0％和117.9％,其延伸率为6.3％.拉伸断口观察表明,SiCp/Al MMC断裂机制为界面脱粘和SiC团聚体的脆断.该复合材料具有高强度的原因是基体的微观结构发生了变化,用位错密度强化和弥散强化机制对Al MMC的强化作用进行了评估,预测结果与实验值符合得很好.

The sub-micrometric Sic particulates reinforced pure aluminum metal matrix composite (Al MMC) was fabricated by a powder metallurgy technique. The microstructure of the Al MMC was observed, and the tensile properties were measured. The results show that the 15% SiCp (150 nm)/Al MMC exhibits an ultimate tensile strength of 342.3 MPa and a yield strength of 272.4 MPa, these values are 89.0% and 117.9% higher than those of the corresponding matrix respectively, and the elongation of the Al MMC is 6.3%. The tensile fracture surface shows that the damage mechanisms of the Al MMC involve interfacial failure and brittle damage of SiC agglomeration. The reason that the Al MMC has much higher yield strength is the change of matrix microstructure. Dislocation density and Orowan strengthening mechanisms are used to evaluate their effects on the matrix yield strength, and the predicted result is consistent with experimental result.