Indentation tests were performed to assess the influence of compositional changes on the mechanical properties of several half-Heusler compounds with the general composition Zr0.5Hf0.5Co1-x
Sb0.99Sn0.01 (x=0.0,0.1,0.3,0.5,0.7). These samples were synthesized by high temperature solid-state reactions and were consolidated by hot-pressing. Indentation measurements were obtained using both microhardness testing (Vickers) and depth-sensing nanoindentation. These measurements were used to determine the microhardness and the elastic modulus of each half-Heusler compound. The Vickers hardness values were found to range between 876 and 964. A slight increase in hardness was observed with the addition of iridium. The elastic stiffness values ranged from 229 GPa to 246 GPa. Here, a slight decrease in stiffness was observed with the addition of iridium.