Observation of incongruent melting in Cu10Hf7

Differential thermal analysis, scanning electron microscopy, and x-ray microanalysis are used to show that the intermetallic compound Cu10Hf7, previously reported as melting congruently at 1025 °C, melts incongruently to CuHf2 and a Hf-Cu liquid at that temperature. A eutectic point previously reported at 43.6 at.% Hf and 980 °C does not exist.