Correlation between Micro hardness and Microstructure of CMT Welded AA 7075 Al Alloy

Abstract

The Cold Metal transfer process have recently gained significant importance in the manufacturing sectors due to its excellent droplet transfer of consumable in the molten pool with no spatter. The 7xxx series of Al alloys are the most preferable material to dynamic applications. Hence, in this research work, the AA7075 Al alloys were joined using an advanced TPS 400i Cold Metal Transfer (TCMT) welding machine in order to understand the homogeneity of the weldment with respect to its microhardness and the correlation between the microhardness and microstructure of the joints were analyzed. Finally, it was found that the hardness was decreased in the Weld Zone (WZ) compared to Heat Affected Zone (HAZ) and the Base Metal (BM) and also the metallurgical characterization reveals that the joint is free of defects and fine grains were observed in the WZ.