High-Temperature Mechanical Properties of the Platinum Group Metals

In order to provide reliable data on the high-temperature deformation behaviour of iridium, the high-temperature material properties such as stress-rupture strength, high-temperature tensile strength and creep behaviour are determined for pure iridium in the temperature range 1650 – 2300°C. Analyses of the stress-rupture curves and the creep behaviour of pure iridium samples at 1650°C, 1800°C and 2000°C imply that the fracture behaviour is controlled by two different fracture mechanisms depending on test conditions, in particular applied load and test temperature. The existence of the different fracture modes is confirmed by SEM examination of the fracture surface of samples ruptured at high temperatures. Anomalies in the creep curves and the results of high - temperature tensile tests indicate that dynamic recrystallisation plays an important role in the high - temperature deformation behaviour of pure iridium.