INVESTIGATION OF THE HIGH-TEMPERATURE PLASTICITY OF MATERIALS BY INDENTATION MEASUREMENTS

High temperature mechanical properties of metallic and non-metallic materials were investigated by impression creep test. The stress exponent and activation energies obtained are presented. In the case of the A1-3%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. For non-metallic materials the indentation measurements resulted in for the case of a silica glass of about 1 for the value of n while for a ceramic-glass material n approximate to 1.5 was obtained. In this latter case the activation energy was also very high (similar to 1000 kJ/mol).