Microstructural investigation of laser remelted electrospark deposited layer on IN738LC super alloy

Electrospark deposition method has been used for creating an intermediate layer on the IN738LC superalloy for subsequent laser welding or laser cladding. With using proper Electrospark deposition parameters a crack free or at least less crack susceptible layer can be formed by same filler metal on this alloy. ESD layer has unique microstructure consists of columnar gamma phase. Because of very rapid cooling rate involved in electrospark deposition method, the layer with very low elemental segregation can be obtained. Having fine grain microstructure in comparison to as cast base metal, ESD layer is more crack resistance. Laser remelted ESD layer is dense and the ESD defects like lack of fusion between layers and porosity are eliminated in laser remelted layer. Hardness results show lower hardness value for remelted laser area in comparison with ESD layer. Furthermore, no solidification or liquation crack found in remelted layer.