Friction Stir Powder Additive Manufacturing of Multi-track Depositions of Al 6061 Alloy for Cladding and 3D Printing Applications

Abstract

This study explores friction stir powder additive manufacturing of multi-track single-layer (MTSL) and multi-track multi-layer (MTML) depositions of aerospace grade Al 6061 for cladding and 3D printing applications respectively. Two MTSL depositions, each comprising of four deposition tracks with 2 mm and 4 mm overlap, were manufactured on Al 6061 substrate using the previously identified optimum process parameters. For 25 mm bending displacement, MTSL with 2-mm overlap failed at the interface between the adjacent tracks without showing any abrupt drop in bending force whereas 4 mm overlap MTSL did not fail because of stronger interface bonding. Therefore, 4 mm overlap was used to manufacture MTML deposition consisting of four depositions tracks and four deposition layers. MTML deposition failed at 17 mm bending displacement with an abrupt drop in bending force due to more deposition layers and their delamination. Bending force increased slightly because of regaining some strength from the substrate. Microhardness decreased marginally at overlapping regions in MTSL and MTML depositions compared with the non-overlapping regions because of localized high temperature caused by compressive forces. Tensile properties of Al 6061 alloy MTML along the track direction are comparable with corresponding single-track multi-layer deposition indicating good bonding between the tracks. © 2023, The Minerals, Metals & Materials Society.