Weld Heating Rate and the Constitutional γ’ Particles of IN738LC Super Alloy

  • Program
  • Room 2F East
  • September 12 2018
  • 3:45 pm - 4:10 pm

Inconel 738LC is a widely used cast precipitation-hardened nickel-based super alloy in gas turbine engines applications. Heat affected zone (HAZ) grain boundary liquation cracking during welding is often regarded as one of the most serious problems affecting precipitation-hardened nickel-based super alloys. The purpose of this study was to investigate the liquation cracking of precipitation hardened nickel-based super alloy (IN738LC) during a very high heating rate fusion welding process (Pulsed Laser Welding).

It was found that very high heating rates of low-power pulsed laser welding can significantly reduce the liquation susceptibility of y’ particles at weld HAZ. Contrary to previous reports, the liquation of y’ particles was not observed in the heat affected zone of low power pulsed Nd:YAG laser welded IN738LC alloy. Gleeble simulation at several heating rates and peak temperatures also revealed that the extent of y’ liquation decreased with heating rate increasing above the critical heating rate for liquation.