Developing new microstructure through laser melting of electrospark layer of precipitation hardened nickel based superalloy

Abstract

Highly oriented fine microstructure was achieved through laser melting of electrospark layer of a precipitation hardened nickel based superalloy. Using electron back scattered diffraction analysis, it was found that the new layer has preferred orientation toward the surface. This microstructure grows epitaxially on the electrospark layer, which consists of very fine grains. Having lower elemental segregation and finer grain size, this new modified microstructure has higher hot cracking resistance compared to the conventional autogenous laser weld microstructure on cast alloy.