Microstructural and micro-hardness study on the fabricated Al 5083-O/6061-T6/7075-T6 gradient composite component via a novel route of friction stir additive manufacturing

Abstract

Friction stir additive manufacturing (FSAM), which is a recently developed technology based on the principle of friction stir welding (FSW) can be utilized to join metal alloys additively in their solid-state. In the current investigation, Al 5083-O/6061-T6/7075-T6 gradient composite component of 8.8 mm build height was fabricated by using the FSAM technique. Microstructural, microhardness, and X-Ray diffraction (XRD) characterization tests were conducted on the fabricated build to investigate the microstructural changes and microhardness variation in subsequent layers of the build. SZ possesses a fine-grained microstructure but thermally mechanical affected zone (TMAZ) and heat-affected zone (HAZ) regions show coarse and elongated grains. A higher microhardness zone was noted in the SZ of each layer with a maximum hardness of 151 HV0.1 in the SZ of the top layer. Lower microhardness was observed in the TMAZ and HAZ of each layer of the build. However, the lowest microhardness of 51 HV0.1 was noted on the retreating side of HAZ on the bottom layer. XRD characterization test was conducted on the SZ of the build cross-section. Aluminium peaks along with some minor peaks of Al0.4Zn0.6 were observed.