Heat affected zone microfissuring in a laser beam welded directionally solidified Ni3Al-base alloy

The laser beam weld heat affected zone (HAZ) microstructure of a newly developed aerospace alloy, IC 6, was examined. HAZ microfissuring was observed and found to be associated with grain boundary liquation facilitated by subsolidus eutectic-type transformation of the alloy’s major phase, γ′ precipitates, and interfacial melting of M6C-type carbide and (Mo2Ni)B2-type boride particles.