Effect of adding IN718 on crack inhibition, microstructure, and mechanical properties of selective laser melted IN738LC alloy

Abstract

Crack inhibition during additive manufacturing (AM) of superalloys with complex compositions is an important but challenging task. In this work, we explored the effectiveness of reducing the Al and Ti content by adding IN718 superalloy powders to realize crack suppression during selective laser melting (SLM) of IN738LC superalloy. The effect of IN718 superalloy powder addition on the crack formation, microstructure, and mechanical properties of the SLMed 738LC superalloy was investigated in detail. The results show that adding the IN718 superalloy powder can effectively inhibit the formation of cracks in the SLMed IN738LC superalloy while improving the mechanical properties. The SLMed IN718-25 % sample shows the best mechanical properties, with a tensile strength of 937 MPa and an elongation of 30.6 %. Also, its hardness distribution tends to be more uniform. The excellent mechanical properties are mainly attributed to the effective crack suppression by adding a certain percentage of IN718 to the IN738LC alloy. Our work provides a simple method to effectively inhibit crack formation during the AM process of nickel-based superalloys.