Solid solubility of hafnium in nickel

The solvus curve of the nickel-rich domain of nickel-hafnium phase diagram is determined by the parametric method based on the cell parameter measurements by X-ray diffraction. The maximum Hf solid solubility at the eutectic temperature is determined to be 1.3 at.%. On the other hand, it was found that the effect of Hf additions on the cell parameter of the Ni(Hf) solid solution is not predictable by the elastic theory. Furthermore, the determined enthalpy of Hf in Ni(Hf), containing more than 0.3 at.%, is around 113 kJ/mol. It is however about 17 kJ/mol for the Hf-lean Ni(Hf) solid solution. (C) 1998 Elsevier Science S.A.