Influence of heat treatment on microstructure and mixed-mode fracture behaviour of additively manufactured 316L stainless steel

Additive manufacturing (AM) has significant advantages over traditional production methods, including reduced material waste and enhanced design freedom. One of the dominant AM processes, laser powder bed fusion (L-PBF), relies on important process parameters—scanning speed, layer thickness, and laser power—whose settings determine the microstructure and mechanical properties of L-PBF-printed parts. In this study, correlation of microstructure and macro-mechanical fracture behaviour of L-PBF-printed 316L stainless steel material is investigated. It also contains comparison of as-built and heat-treated specimens at 700 °C, 900 °C, and 1100 °C on force-displacement curves and microstructure. Arcan fixture was employed to analyse mixed-mode fracture behaviour, and microstructural examination of fracture surfaces uses scanning electron microscopy, X-ray diffractometer, and electron backscatter diffraction. Apart from that, Johnson Cook plasticity theory was applied to as-built Arcan specimens under pure shear, mixed mode, and tensile loadings with Abaqus/CAE software. Influence of porosity in mechanical behaviour was sought on comparing experimental and numerical results. As a result, numerical results were extremely in line with experiments. The findings provide a correlation of micro-scale properties, fracture properties, and L-PBF process parameters and provide insights on the optimization of AM component design and performance.