Effect of Crucible Type on γ' Precipitates and Stress Rupture Properties of Rene 80 Superalloy

Rene 80 is a cast alloy which widely used in turbine blade industry. The purpose of this investigation is to study the effect of crucible type (Zirconia and Alumina) in vacuum induction melting furnace (VIM) with alumina rucible on the amount of gases, γ' precipitates and stress rupture properties of Rene 80 superalloy. For this purpose, the amount of O, N gasses and chemical composition were analyzed. The microstructure was assessed by scanning electron microscopy (SEM) and stress rupture properties was performed at 980˚C. The results showed that Crucible type has no considerable effect on the γ' size and morphology but γ' volume fraction increased about 3% in the alloy melts in Zirconia crucible in comparison to Alumina one. The result of mechanical test showed that the stress-rupture life of sample melts in Alumina and Zirconia crucibles are 22.6 and 24.7 respectively because of reducing γ' volume fraction in the alloy melt in Alumina crucible.