Mechanical and microstructural properties of as-built and machined 308L-Si WAAM-CMT walls
摘要
This study focuses on the characterization of 308L-Si stainless steel parts fabricated using the wire arc additive manufacturing process and aims to evaluate the influence of machining on the mechanical and microstructural properties of the manufactured parts. Initially, the process parameters and deposition strategy were validated. Two walls were manufactured under identical conditions, one of which was subsequently machined. Tensile specimens were obtained using CNC laser machine to obtain two sample series: as-built and machined conditions. Subsequently, tensile testing coupled with digital image correlation, along with electron backscatter diffraction analysis, was performed. Tensile specimens were cut at different orientations (0°, 45°, and 90°) relative to the build direction. The tests revealed anisotropic mechanical behavior in both as-built and machined conditions. The results demonstrate that machining enhances overall mechanical properties, increasing the tensile strength by up to 43.7% at 0° and the fracture strain by up to 42% at 90°, while anisotropy remains present. Electron backscatter diffraction and microhardness analyses confirm these observations, revealing a microstructure characterized by directional solidification patterns and significant grain size variations along the build direction. Finally, significant differences in strength and ductility were observed between as-built and machined states, underscoring the importance of comprehensive mechanical characterization to ensure reliable performance in industrial applications.