A martensitic stainless steel AISI420 fabricated by selective laser melting (SLM) and post-processed by austenitizing and tempering heat treatment was investigated in this study. The as-fabricated SLMed AISI420 showed a strong mechanical property anisotropy and low ductility in the longitudinal direction. Detailed microstructural characterization revealed the presence of austenite and a relatively sharp solidification texture in the as-fabricated state, while the sharp texture was considered as the cause for the mechanical property anisotropy. In contrast, a fully martensitic microstructure with a very weak texture was achieved after the austenitizing and tempering heat treatment. The mechanical property anisotropy was also fully eliminated, witnessing a significant improvement in the ductility, and thus, comparable mechanical performance with the wrought product was achieved in this study.
- Electron backscattered diffraction (EBSD)
- Martensitic steel
- Selective laser melting
- Tensile testing