Influence of Hatch Strategy on Crystallographic Texture Evolution, Mechanical Anisotropy of Laser Beam Powder Bed Fused S316L Steel

Abstract

The correlations between process conditions, microstructure, and mechanical properties of additively manufactured components are not fully understood yet. In this contribution, three different hatch strategies are used to fabricate rod‐like samples from S316L stainless steel, which are further investigated using synchrotron diffraction, optical microscopy, and tensile tests. The results indicate the presence of ⟨110⟩ biaxial and fiber textures, whose sharpness depends on the applied hatch strategy. Mechanical tests reveal a strong correlation of the samples’ response to the observed anisotropy in the plane perpendicular to the build direction. Even though the average yield and ultimate tensile strengths of around 475 and 500 MPa, respectively, do not differ significantly, the stress–strain behavior can be correlated with the observed in‐plane anisotropy. Particularly, twinning‐induced plasticity, a distinct increase of the work hardening rate at larger strains and elliptical necking are observed in some samples with biaxial (Goss) texture. These findings indicate that texture design by means of applying dedicated hatch strategies can be used to effectively tune the multiaxial deformation behavior of components produced by laser powder bed fusion.

Effects of build direction and microstructure on fatigue crack growth behavior of Ti6Al4V fabricated by laser powder bed fusion

“…Based on the study of the effect of microstructure and pore defects on fatigue properties, many researchers have used heat treatment, hot isostatic pressing (HIP), and other methods to reduce the anisotropic behavior. [24][25][26][27] Kumar et al 28 reduced the anisotropic behavior and improved the ductility, fracture toughness, and resistance to FCG of LPBF-fabricated Ti6Al4V samples by a twostep cooling heat treatment process. However, the yield strength and tensile strength were reduced by about 20%.…”