Effect of microstructure on the electrochemical dissolution behaviour of Hastelloy® X superalloy processed by selective laser melting and heat treatments

Abstract As a proven and highly efficient processing technique, electrochemical machining (ECM) is used for machining difficult-to-cut Ni-based superalloys (such as Hastelloy® X [HX] fabricated via selective laser melting [SLM]) with complex shapes. However, the metallic surface is susceptible to passive film formation to reduce the dissolution rate of HX under low current density conditions during the ECM process. This study focused on optimising microstructures for SLM-fabricated HX via heat treatment to enhance its electrochemical dissolution behaviour. The rates of electrochemical dissolution with different heat treatments increased in the following order: as-received