A Comparison of the Microstructure, Mechanical Properties, and Corrosion Resistance of the K213 Superalloy after Conventional Casting and Selective Laser Melting

Abstract

K213 superalloy was fabricated by conventional casting and selective laser melting (SLM). The microstructures of the two samples were examined, and the mechanical properties and corrosion resistance of these two kinds of K213 alloy were comparatively studied. The results show that segregation of Ti occurs at the grain boundaries of the as-cast alloy, resulting in the formation of MC carbide. Many microcracks were formed in the SLM sample. Premature fracture of the as-cast alloy is caused by the precipitation of the harmful phase (Ti, Mo, Nb)C (MC). The MC carbides and microcracks in the as-cast and SLM alloys, respectively, induce tensile fracture. In comparison, the strength of the SLM sample is greater, while the elongation of the as-cast sample is greater. The oxidation resistance of the SLM sample is better at a high temperature of 800 °C. This is due to the relatively uniform composition and microstructure of the SLM alloy. However, the corrosion rate of the SLM alloy is accelerated during the electrochemical immersion corrosion process due to the existence of microcracks.