Investigating the impact, wear, metallurgical, and tensile characteristics of cold metal transfer wire arc additive manufacturing fabricated Al5356 walls

This study examines the mechanical and microstructural features of a 36-layer Al5356 wall constructed on an Al6061 substrate utilizing Cold Metal Transfer-Wire Arc Additive Manufacturing. Using tensile, impact, and wear tests, microhardness measurements, fractography, and Electron Backscatter Diffraction (EBSD), property changes along the wall’s height were assessed, notably in the top, middle, and bottom. Performance varied along the building direction. The top layers had 30% higher ultimate tensile strength and impact toughness than the lower levels. EBSD found finer grain structures and more high-angle grain boundaries at the top, increasing strength and critical resolved shear stress. Microhardness rose from bottom to top, with the lowest region 20% lower. Due to surface oxide formation, top layers exhibited stronger wear resistance, decreased friction, and narrower and shallower wear tracks. Due to higher heat input and thermal cycling during deposition, coarser grains and mechanical degradation caused reduced bottom layer performance. These findings highlight the relevance of thermal history in defining WAAM-fabricated aluminum structures.