Internal friction characteristics of Ti51.5Ni26.0Pd22.5 thin films formed by sputter deposition

The internal friction and the modulus have been measured on Ti51.5Ni26.0Pd22.5 films under tension load, at three frequencies 0.5, 1.0, 5.0 Hz. in a wide range of temperatures covering the orthorhombic martensite and the reverse transformations. The effect of heat treatment and frequency on the internal friction has also been investigated. Only a transition around the orthorhombic transformation took place and a very sharp step-type internal friction was observed for all films with three kinds of heat treatments. The elastic modulus evolution reversed to internal friction change and a remarkable depression of the modulus corresponded to the internal friction peak. The internal friction of the films was enhanced by crystallization at 750 °C and the highest internal friction obtained at frequency 0.5 Hz. Ageing treatment at 450 °C after crystallizing at 750 °C promoted the peak of internal friction appearing and accelerated the microstructure variation. A high damping capacity of Q− 1 = 0.05 or 0.06 was reached in the films crystallizing at 750 °C with or without ageing at 450 °C respectively and sustained from room temperature to 100 °C.