Contribution of constitutional liquation of gamma prime precipitate to weld HAZ cracking of cast Inconel 738 superalloy

The weld heat affected zone (HAZ) cracking in cast Inconel 738 superalloy has been examined. Constitutional liquation of the main strengthening phase of the alloy γ′, which is also present in significant volume after pre-weld heat treatment, was found to contribute significantly to grain boundary liquation and its attendant cracking in the HAZ.