Laser cladding of aluminum alloy 6061 via off-axis powder injection

Abstract

Abstract Laser cladding is a surface enhancement and repair process in which a high-powered laser beam is used to deposit a thin (0.05\u202fmm to 2\u202fmm) layer of material onto a metal substrate with no cracking, minimal porosity, and satisfactory mechanical properties. In this work, a 4\u202fkW High Power Diode Laser (HPDL) is used with off-axis powder injection to deposit single-tracks of aluminum alloy 6061 powder on a 6061-T6511 substrate. The process parameters were varied to identify the possible processing window in which a successful clad is achieved. Geometrical characteristics were correlated to the processing parameters and the trends were discussed. Micro-hardness testing was employed to examine the mechanical properties of the clad in the as-deposited and precipitation heat treated conditions. Transmission electron microscopy (TEM) was used to investigate the precipitate structures in the clad and substrate as an explanation for the hardness variations. Experiments were completed on two substrate widths to understand the effect of domain size on the process map, layer size, and hardness.