Effect of hot isostatic pressing on the microstructure and mechanical properties of selective laser melting FeCrAl ODS alloys

Abstract

Additive manufacturing technology has potential in the field of oxide dispersion strengthened (ODS)alloy preparation, but the inability to achieve complete densification is also regarded as a key factor affecting its application. In this work, FeCrAl ODS alloy was manufactured by selective laser melting (SLM) technology, and the as-deposited sample were post-treated by hot isostatic pressing (HIP) technique. Following HIP, the porosity of the SLM ODS alloys decreased significantly and the texture intensity along the deposition direction weakened. Under the high temperature and high-pressure conditions of HIP process, there is nanoparticle diffusion reprecipitation and Ostwald ripening. After the HIP treatment, the dislocation density decreased and large particles precipitated along grain boundaries, resulting in a decrease in the microhardness of the sample. The tensile tests shows that the strength and ductility of the samples decrease following HIP treatment. The loss of mechanical properties is related to the precipitation of undesirable phases.