Processing of nickel based superalloy MAR M-247 by means of high-temperature - selective laser melting (HT - SLM)

Nickel based superalloys, such as MAR M-247 are widely utilized for turbomachinery due to their high temperature creep resistance and good oxidization behavior. Initially developed for processing by means of casting, MAR M-247 is classified as difficult to weld, posing a challenge during processing by Selective Laser Melting (SLM) due to excessive crack formation. The present paper aims at suppressing crack formation by decreasing thermal gradients and, thus, transient strain during SLM as a result of high - temperature preheating up to 1200 degrees C. Comparative analyses are performed, capturing the influence of high - temperature preheating on crack formation, grain size and microstructure.