Analysis of residual stress field in graded stainless steel, from austenite to ferrite built by Dual Wire Arc Additive Manufacturing Tungsten Inert Gas

Wire Arc Additive Manufacturing (WAAM), especially when incorporating multiple materials, is a promising process but faces challenges related to thermal cycling, which induces complex thermal, metallurgical, and mechanical phenomena, leading to residual stress and strain. These issues cause dimensional inaccuracies and reduced mechanical properties, complicating the manufacturing process. Dual-WAAM (D-WAAM) allows for more complex part production but introduces new mechanisms responsible for stress and strain that remain poorly understood. This proposal aims to explore the mixing effects of two stainless steels having different thermomechanical properties on stress development in the context of D-WAAM.
Stress analyses on ENGIN-X will provide insight into how thermal cycling and gradients impact residual stress and strain in both constant compositions and graded samples. Stress fields will be measured along the three orthogonal directions of the part, matching relevant directions of the welding process, to capture a comprehensive understanding of the residual stress distribution.
This research will enhance knowledge about how specific alloy combinations and microstructures affect stress and strain in D-WAAM, providing valuable data for numerical models to ultimately predict part mechanical behaviour. The outcomes are expected to guide the selection of optimal alloy combinations to minimize residual stress in D-WAAM parts. Additionally, this work supports ongoing PhD research.