Significantly improving the oxidation and spallation resistance of a MCrAlY alloy by controlling the distribution of yttrium

Abstract

The NiCoCrAlY alloy with uniform yttrium distribution was fabricated via powder milling and spark plasma sintering. After powder milling, yttrium was uniformly distributed in the alloy in the form of Ni-Y precipitates (50–150 nm) and nano-sized Y2O3 particles (5–30 nm). It was found that the uniform yttrium distribution could: 1) lower thermally grown oxides (TGO) growth rate; 2) reduce the growth stress in the TGO; 3) suppress S segregation to the interface and the formation of interfacial imperfections (e.g. oxide intrusions, pores). Consequently, the oxidation and spallation resistance of the TGO was significantly improved.