Investigation of the High Temperature Plasticity of Materials by Indentation Measurements

High-temperature mechanical properties of metallic and nonmetallic materials were investigated by impression creep test. The stress exponent and activation energies obtained are presented. In the case of the Al-3 pct Mg solid solution alloy it was shown that the stress exponent and the activation energy depends on the applied stress. They were found to be 3 and 148 kJ/mol in the lower stress regions and 4.6 and 129 kJ/mol in the higher stress regions, respectively. Indentation measurements for nonmetallic materials are reported. For the case of a silica glass n of about 1 was obtained, while for a ceramic-glass material n of about 1.5 was obtained. In this latter case the activation energy was also very high. (Author)