Mechanical behaviour of pure iridium in high strain-rate and high temperature loading conditions

The introduction in recent years of new, extremely energetic particle accelerators such as the Large Hadron Collider (LHC) gives impulse to the development and testing of new materials. Some of the machine components are designed to operate in harsh radioactive environment highly solicited from thermo-structural point of view. The refractory metals and their alloys are good candidate since they exhibit a good combination of properties, among which high melting point, good strength and stability at extremely high temperature, and excellent resistance to thermal shock. The main goal of this study is the investigation of the mechanical behaviour at different temperatures and strain-rates in tensile loading condition of pure iridium. A series of tests at room temperature at different strain-rates (from 10-3 s-1 up to 104 s-1) was performed in order to obtain information about the strain and strain-rate sensitivity of the material. In addition, a series of tests at different temperatures in both quasi-static and high strain-rate loading conditions was performed in order to obtain information about the thermal softening of the material (from room temperature up to 1250 °C). The experimental data were used to identify a strength model able to reproduce the material behaviour under different loading conditions.