Effect of Processing Parameters and Thermal History on Microstructure Evolution and Functional Properties in Laser Powder Bed Fusion of 316L

In this study, we investigate and quantify the causal effects of processing parameters and part-scale thermal history on the evolution of microstructure and mechanical properties in laser powder bed fusion (LPBF) of Stainless Steel 316L. While prior work has correlated processing parameters with flaw formation, microstructural features, and properties, the role of thermal history has remained underexplored. To address this gap, we propose a computational approach that directly links thermal history to microstructural evolution and part performance.Tensile test coupons were fabricated under varying LPBF processing conditions and characterized for grain morphology, size distribution, texture, porosity, and microhardness, as well as yield and tensile strengths. A computational model, validated against experiments, was used to predict the thermal history of each coupon. From these predictions, temperature gradients and subsurface cooling rates were extracted and correlated with the measured microstructure and properties.

By establishing this process–thermal–structure–property relationship, our work lays the foundation for physics-based prediction, control, and optimization of microstructure and functional properties in LPBF.