Effect of yttrium on microstructure and properties of Ni3Al base alloy IC6

The effect of yttrium on the microstructure of alloy IC6 was examined by scanning electron microscopy (SEM), the energy dispersive spectrum (EDS) technique of electron probe micro-analyzer (EPMA) and transmission electron microscopy (TEM). The results show that the microstructure of alloy IC6 with addition of 0.04–0.12 wt% yttrium has no obvious difference compared with that of the alloy without yttrium, and that Ni3Y and Mo1.24Ni0.76 precipitate in the interdendritic area surrounded by large size γ′ phase in the alloy with addition of 0.20–0.30 wt% yttrium. The effect of yttrium on high temperature static and cyclic oxidation resistance, stress rupture properties and thermal fatigue resistance was also investigated in this study.