Indentation Creep Behavior of Mg-10Gd-3Y-0.5Zr (wt.%) Alloy at Elevated Temperatures

Abstract

The indentation creep behavior of a cast Mg-10Gd-3Y-0.5Zr (GW103) alloy was investigated by flat cylindrical indenter at temperatures ranging from 250 to 325 °C and stresses ranging from 80 to 505 MPa. The indentation creep stress exponents varied from 1.36 to 5.10, which were lower at lower temperatures and stresses. The creep activation energies increased from 106.11 kJ/mol to 190.65 kJ/mol with increasing stress. Dislocation-controlled creep was suggested in high temperature and stress regime, while grain boundary sliding could contribute more at lower temperatures and stresses. The zone just beneath the indenter almost maintained the same during indentation creep, while the zone inside cycle segments under the indenter deformed severely. The zone at the edge of the indenter underwent largest stress and strain, resulting in broken of grain boundaries and bending of most intragranular precipitates.