Experimental determination of phase equilibria in the Ni-Hf-Si ternary system

The phase equilibria of the Ni-Hf-Si ternary system at 1000 °C and 1100 °C have been experimentally investigated by back-scattered electron (BSE), electron probe microanalyzer (EPMA) and X-ray diffraction (XRD) on the equilibrated alloys. In the present study, two isothermal sections were determined by a series alloys consisted of binary phases, ternary compounds or solid solutions. Four ternary compounds (τ1, τ2, τ3, τ4) were identified in these isothermal sections, and one new phase named τ9 (Ni9Hf19Si22) was firstly observed both at 1000 °C and 1100 °C. The newly determined phase equilibria in this system will provide useful information for the thermodynamic assessment and compositional design of Ni-based alloys.