Variation of liquation cracking susceptibility for over–aged 247LC superalloy repair weld heat–affected zone

In this study, the liquation cracking temperature range (LCTR) of over-aged 247LC superalloy repair welds was quantitatively evaluated using spot-Varestraint testing, especially for application in weld heat-affected zone (HAZ). The metallurgical mechanism susceptibility and variation LCTRs superalloys clarified by analyzing microstructural characteristics at surface, thermodynamic calculations. From tests materials, LCTR to be 410 620 K 500 1000 h specimens, respectively. These results demonstrate that face significant serious HAZ. Based on local element distributions analyzed transmission electron microscopy Thermo-Calc calculations, underlying high overaged materials could attributed precipitation fine MC M6C carbides during over-aging treatment. promote interface between gamma phase temperatures lower than equilibrium solidus (1530 K) 247LC. estimated initiation MC/γ γ/M6C interfaces were 1125 1420 K,