Mechanical properties of Rh-based L12 intermetallic compounds Rh3Ti, Rh3Nb and Rh3Ta

A preliminary study of the mechanical properties of Rh-based L12 intermetallic compounds Rh3Ti, Rh3Nb and Rh3Ta is carried out by micro-vickers hardness tests at room temperature and compression tests at various temperatures ranging from room temperature to 1673 K. A cold-rolling test is also conducted on a Rh3Ti plate. Although high temperature ductility-loss is observed in all compounds, Rh3Ti shows good ductility at all temperatures investigated. Both Rh3Nb and Rh3Ta show a weak positive temperature dependence of strength (stress anomaly) at around 1273 K which is about half the melting point for both intermetallic compounds. The stress anomaly is discussed in terms of a phase stability concept based on the Kear–Wilsdorf (K–W) mechanism. High work hardening rates of Rh3Nb and Rh3Ta, which cause high vickers hardness at room temperature, are also attributed to the K–W mechanism.