Creep properties and controlled creep mechanism of as-cast Mg-5Zn-2.5Er alloy

The creep behaviors of as-cast Mg-5Zn-2.5Er alloy (mass fraction, %), under various applied stresses (50-70 MPa) and creep temperatures (150-200 degrees C) for 100 h, were investigated. The stress exponent n is in the range of 1.5-5.8, and the activation energy Q. is in the range of 28.3-77.1 kJ/mol. With respect to the calculated n and a as well as the microstructures after creep, it is suggested that there is a transition region between grain boundary sliding(GBS) dominated creep to dislocation creep mechanism (from n<3 to n>3), arising in the steady-stage creep rate value of 2.89 x 10(-9) s(-1).