Creep behavior of Mg-2 wt.%Nd binary alloy

A binary magnesium alloy, Mg-2 wt.%Nd, has been prepared. Under the condition of temperature between 150 and 250 degrees C and applied stress between 30 and 110 MPa, the alloy exhibits good creep resistance due to both solution-hardening and especially precipitation-hardening. Tiny precipitates forming dynamically during creep have been observed, which play an important role in restricting dislocation movements. When the creep tests are carried out at the temperature range between 150 and 250 degrees C, the stress exponents lie in the range of 4.5-7.1 at low stresses, which is consistent with the "five-power-law". The values of stress exponent increase up to 9.8-29.5 at high stresses indicate power-law breakdown. When the creep tests are carried out under the applied stress between 30 and 90 MPa, the apparent activation energy values vary from 70.0 to 96.0 kJ/mol at low temperatures, but increase to 199.9-246.1 kJ/mol at high temperature range. Dislocations in basal plane are activated in the primary creep stage, but as creep goes on, they are observed in non-basal plane. The creep is mainly controlled by both dislocation-climb and cross-slip. (C) 2009 Elsevier B.V. All rights reserved.