Evaluation of the microstructure and high-temperature ductility behavior of ۳۱۶L SS produced by selective laser melting process

Selective laser melting is one of the several free-form additive manufacturing techniques in which the metallic powder bed is melted layer upon layer by a highly focused laser beam to produce structural components with intricate geometries and superior properties. This research investigated the microstructure and mechanical properties of the ۳۱۶L made by SLM. After manufacturing parts by SLM, a hot pressure test was performed on the samples at temperatures of ۸۰۰°C, ۹۰۰°C, ۱۰۰۰°C and ۱۱۰۰°C and strain rates of ۱۰-۱s-۱,۱۰-۲s-۱ and ۱۰-۳s-۱. The existence of a peak point in the true strain stress curves obtained from the hot pressure test indicates the phenomenon of dynamic recrystallization. Examining the microstructure of the samples, the phenomenon of dynamic recrystallization was also proved. Then by examining Zener Holman's equation and its constants the activation energy for ۳۱۶L steel was calculated as ۴۷۸ kJ/mol. The process map of this steel at ۰.۸ strain was obtained and the stable and unstable regions were identified. Meanwhile, to examine the accuracy of the process maps, the microstructure of the samples in these regions was also investigated. The light microscope images of the microstructures of the samples show the phenomenon of dynamic recrystallization in stable areas and metallurgical defects such as cavities and cracks in unstable sample.

کلیدواژه ها:

SS ۳۱۶L ، Additive Manufacturing ، SLM method ، Hot Deformation