Microstructure and Mechanical Properties of Cu-Coated Al 2 O 3 Particulate Reinforced 6061 Al Metal Matrix Composite

In the present work an attempt is made to synthesize 6061Al – Cu coated Al 2 O 3 particulate metal matrix composite by two stage melt stirring method. 6061Al alloy is reinforced with copper coated Al 2 O 3 particulate through compo casting technique. Compo casting technique is adopted over single stage melting stirring process as this eliminates wettability problem of particulates and results in better properties of MMC. The MMC is obtained by incorporating 3, 6 and 9 wt.% of un-coated Al 2 O 3 and Cu-coated Al 2 O 3 with 6061Al alloy. Microstructural analysis reveals that Cu coatings around Al 2 O 3 particulates have improved the wettability at the interface resulting in better incubation and avoiding segregation of particulates in the melt which are evident from SEM microphotographs. Mechanical properties like density, hardness and tensile strength were studied for both copper coated and uncoated Al 2 O 3 reinforced composite at room temperature. Significant increase in mechanical properties was observed for copper coated Al- Al 2 O 3 composite due to improved wettability and uniform distribution of particulates within 6061Al matrix compared with Al- Al 2 O 3 composite without Cu coatings.