In the present work, three different superalloy filler powders IN625, IN939 and IN738 subjected to direct metal deposition on IN738 substrate. The repair process was done on lower part of a blade airfoil. Then, the cross-section of repaired zones was characterised using optical microscopy, scanning electron microscopy and phase analysis. Also, the hardness of repaired zone, substrate and heat-affected zone were investigated. The results showed, in a certain processing parameter, the crack-free precipitates of IN625 and IN738 was obtained. For IN939, a macro-crack along the build direction was observed. Due to the difference in the growth direction of the dendrites on both sides of the macro-crack, a high-angle grain boundary (HAGB) with a large misorientation angle >15° was formed, resulting in increased cracking susceptibility and development of a macro-crack. No γ’ phase was observed for as-deposited IN738 and IN939 due to cooling rate faster than 105(K.s−1).
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