Microstructural morphology of electrospark deposition layer of a high gamma prime superalloy

High gamma prime superalloy is known for its high susceptibility to welding cracking. However, for these alloys a fusion welding or deposition of crack-free is always expected for repair and refurbishment of their components. On the other hand, electro-spark deposition, though not a new process, microstructural morphology of electro-spark deposited alloy is yet a question of the hour. In this paper, thick deposition layer of a high gamma prime superalloy free from cracking was obtained and its microstructural growth characteristic was investigated. The result shows that countless single-pulse deposition spots randomly overlap with each other to make up the thick deposition layer. Grains grow vertically passing through layers and form long columnar grains with a preferential growth orientation along the build-up direction. The microstructural morphology of the deposited layers shows growing characteristics of cellular structure.