| Abstract Scope |
The tensile creep behavior and microstructure evolution of the T6 state Mg-15Gd (wt.%) alloy were investigated at temperatures from 235 °C to 300 °C and stresses from 50 MPa to 90 MPa. At a fixed creep temperature of 260 °C, the stress exponent n was measured to be 2.6 under 50~80 MPa and 4.8 under 80~90 MPa, respectively, suggesting that the creep deformation mechanism changed from dislocation slip to dislocation climb. Meanwhile, under a defined creep stress of 50 MPa, the activation energy Qc of the alloy was 80 kJ•mol-1 at 235 to 260 °C and 141 kJ•mol-1 at 260 to 300 °C, respectively, indicating the creep deformation mechanism changed from grain boundary sliding to dislocation climb. Furthermore, not only α(Mg) grain size but also the quantity and size of the precipitated phases increased with the increase of the creep stress, the creep temperature and the creep time. |