Elevated Temperature Microstructure Stability of SLM 304L Stainless Steel

At elevated temperatures changes in metallurgical structure can be expected for almost any steel or alloy. In stainless steels, the changes can be grain growth, carbide precipitation, ferrite decomposition, or embrittlement. These phenomena can significantly affect the properties of the stainless steel and would potentially change the functionality of the component. Therefore, the impact of elevated temperatures on the microstructure of SLM 304L stainless steel was studied. The work reported here investigates the influence of different aging times at 300C on microstructure and mechanical properties of stainless steels (304L) fabricated with the Selective Laser Melting (SLM) process. Microstructure and mechanical properties were dramatically effected at temperatures much lower than expected when compared to samples of wrought stainless steel. The stainless steel fabricated using the SLM process was more kinetically active than expected based on previous studies of 304L. Results of this study will be presented along with possible reasons for the higher activity.