The high temperature creep behavior of Mg-6Al-1Nd-1.5Gd alloy under 150

175

200 ℃ and 50

70

90 MPa conditions was investigated by using a high temperature creep device

and the alloy was analyzed for high temperature creep mechanism in the process.The results show that the average stress index and creep activation energy of Mg-6Al-1Nd-1.5Gd alloy reach 4.64 and 73.87 kJ/mol

respectively.The main creep mechanism is characterized by the dislocation creep and grain boundary diffusion.The creep constitutive equation is ε=1.877×10

-8

σ

4.641

exp[-73 865/（RT）].During the high temperature creep of the alloy

the dislocation density in the alloy’s microstructure is increased gradually

and dislocation entanglement and dislocation accumulation appear.In addition

the grains of the alloy are coarsened after creep

and the intermetallic compounds Al

3

Nd and Al

3

Gd are segregated at the grain boundaries.