Anomalous Heat Capacity of TiNi

Calorimetric measurements on a sample of TiNi (50 at.%) show that the heat-capacity maximum at approximately 87°C represents a higher-order transition. The transition was shifted to lower temperatures each time the material was heated through the transition from slightly above room temperature to about 150°–200°C. The transition enthalpy decreased in three such cycles from 4150 to 3375 J/mole TiNi.