Improving the deposition efficiency and mechanical properties of additive manufactured Inconel 625 through hot wire laser metal deposition

Abstract

This study focuses on the advantages of hot wire laser metal deposition (HW-LMD) compared to cold wire deposition technology (CW-LMD) for fabricating Inconel 625 alloy. Initially, a comparative study was conducted through single-pass deposition experiments to evaluate the process characteristics of HW-LMD and CW-LMD. The results showed that by increasing the additional resistance heat by 20% during HW-LMD, a significant 92.5% increase in wire deposition rate and a 60.3% increase in energy efficiency were achieved. Additionally, the wire deposition rate of HW-LMD was 1.5 times as high as that of CW-LMD with the identical total energy input. Subsequently, well-formed Inconel 625 bulks were fabricated using both CW-LMD and HW-LMD techniques. The microstructures and mechanical properties of the as-deposited samples manufactured by the two different processes were comparatively studied. Due to the accelerated solidification rate of the molten pool, the columnar dendrites in Inconel 625 samples prepared by HW-LMD were refined, resulting in an average grain size of 12 µm. Furthermore, the precipitation of the Laves phase at the inter-dendrite regions was suppressed. Consequently, an increased microhardness of 258 HV1.0 for HW-LMD samples was obtained. In addition, the HW-LMD samples also exhibited superior tensile strength and elongation, measuring at 837.4 MPa and 55.2% respectively. Based on the aforementioned findings, HW-LMD has demonstrated outstanding capability in improving productivity and mechanical properties, indicating a promising option for efficient additive repair and manufacturing.