Optimization of mechanical properties in bimetallic ER70S-6/316L components fabricated by wire laser metal deposition

Purpose This study aims to investigate the mechanical performance and fracture behaviour of bimetallic mild steel ER70S-6 and stainless-steel 316L specimens fabricated using the wire laser metal deposition (W-LMD) process. The objective is to optimize process parameters for enhanced strength, ductility and toughness of multi-material additively manufactured components. Design/methodology/approach The research uses an experimental approach using Taguchi L9 design of experiments to evaluate the influence of laser power, layer height and stainless-steel composition on mechanical properties. Open-hole tensile specimens were fabricated through W-LMD, and their mechanical and fracture characteristics were analysed. Grey relational analysis (GRA) was conducted to determine the optimum combination of process parameters. Findings The results indicate that laser power significantly affects residual stresses and layer fusion quality, with 1000 W identified as the optimal power. Layer height showed minimal influence, though 0.8 mm yielded the best mechanical performance. Stainless-steel composition had the most substantial effect, particularly on toughness, with a balanced (˜50%) combination of stainless steel and mild steel achieving the overall optimum properties. Research limitations/implications The study focuses on limited process parameters and two specific metals; future work could include additional alloys, post-processing treatments and microstructural analysis to generalize the findings. The research provides practical guidance for optimizing W-LMD process parameters for multi-material fabrication. Originality/value This work contributes to understanding the relationship between process parameters and mechanical performance in bimetallic W-LMD components. It demonstrates a systematic optimization approach using Taguchi design and GRA to achieve balanced strength and toughness in multi-metal additive manufacturing.