Microstructural stability of 316L stainless steel processed via selective laser melting using different scanning strategies

Abstract

This project aims to evaluate the microstructural stability of AISI 316L austenitic stainless-steel samples processed by selective laser melting (SLM) by choosing four different scanning strategies. In most cases, the printed parts need to be heat treated after processing due to the high residual stresses developed upon processing. The materials processed by this additive manufacturing technique have unique microstructures that vary according to the processing conditions, in particular their dislocation density, depending on the adopted scanning strategy. The samples were processed via SLM and are already available for this study. The materials will be characterized in the "as-processed" condition and after isothermal annealing at 1150°C with emphasis on texture evolution upon static recrystallization. The microstructural characterization will be carried out by means of residual stress measurements in the "as-processed" condition using X-ray diffraction, Vickers microhardness testing and optical and scanning electron microscopy. The corresponding dislocations densities will be evaluated by using two distinct approaches: quantitative metallography from contrast electron channeling images (ECCI) and X-ray diffraction using the Williamson-Hall modified method. Microtexture will be evaluated by electron backscatter diffraction (EBSD) techniques. (AU)