Nanoindentation study of bulk zirconium hydrides at elevated temperatures

The mechanical properties of zirconium hydrides were studied using nano-indentation technique between 25 and 400 °C. Temperature dependency of reduced elastic modulus and hardness of δ- and ε-zirconium hydrides were obtained by conducting nanoindentation experiments on bulk hydride samples with independently heating capability of indenter and heating stage. The reduced elastic modulus of δ-zirconium hydride (H/Zr ratio = 1.61) decreased from ∼113 GPa at room temperature to ∼109 GPa at 400 °C, while its hardness decreased significantly from 4.1 GPa to 2.41 GPa in the same temperature range. For ε-zirconium hydrides (H/Zr ratio = 1.79), the reduced elastic modulus decreased from 61 GPa at room temperature to 54 GPa at 300 °C, while its hardness from 3.06 GPa to 2.19 GPa.