Research Information System
Progress in Additive Manufacturing, 2025 (ESCI, Scopus)
Mechanical anisotropy is a key challenge in wire arc additive manufacturing (WAAM), which is caused by inherent heat transfer conditions and competitive grain growth during solidification. These factors lead to elongated columnar grains oriented toward the substrate, impairing mechanical properties. This study explores a novel torch path strategy to reduce mechanical anisotropy in WAAM-fabricated 316L stainless steel by modifying the conventional torch movement into a forward–backward oscillatory pattern. Two walls were deposited: Norm-316L (conventional unidirectional welding) and FB-316L (oscillatory torch motion). Microstructural analyses were conducted using field emission scanning electron microscopy (FE-SEM) and electron backscatter diffraction (EBSD), alongside mechanical testing. Inverse pole figure (IPF) maps showed dominant columnar grains in Norm-316L, while FB-316L exhibited fewer columnar and more equiaxed grains. Compared to Norm-316L, the FB-316L sample showed a reduction in dominant texture intensity by 42.3%, 65.5%, and 78.2% in the build (BD), transverse (TD), and normal (ND) directions, respectively. Grain boundary maps revealed a transition from predominantly low-angle grain boundaries (LAGBs) in Norm-316L to predominantly high-angle grain boundaries (HAGBs) in FB-316L. Kernel average misorientation (KAM) maps indicated lower local misorientation, reflecting a more homogeneous distribution of dislocations, while grain orientation spread (GOS) analysis revealed reduced intragranular misorientation in FB-316L. Mechanical tests confirmed strong anisotropy in Norm-316L (UTS: 452–529 MPa, El: 28–38.7%, Impact: 81–92 J), while FB-316L exhibited nearly isotropic properties (UTS ≈ 550 MPa, El > 43%, Impact > 96 J).