On as-built microstructure and necessity of solution treatment in additively manufactured Inconel 939

Increased adoption of additively manufactured superalloys has led to the consideration revised heat treatment approaches for these materials. The rapid cooling during additive manufacturing processes been seen suppress gamma prime (γ′) precipitation, which raised possibilities omitting high-temperature solution step that usually precedes ageing alloys. In this work, as-built microstructure a high fraction superalloy Inconel 939 is presented, where absence any γ′ precipitation notable. However, transmission electron microscopy shows presence nano-sized Eta (η) phase. It shown omission leads growth deleterious η phase upon ageing, results in embrittlement tensile loading. concluded at least particular alloy plays critical role establishment required and hence cannot be omitted from treatment.