Establishment of Compression Creep Constitutive Equations of Mg-4Al-2RE Alloy

The compressive creep behavior of Mg-4Al-2RE(AE42) alloy was investigated by using self-made creep test apparatus at temperatures of 125-175 ℃(398-448 K) and compressive stresses of 88-112 MPa.In addition,the compression creep constitutive equation of the alloy was established by regression method.The results indicate that the compressive creep strain and steady state compressive creep rate is increased obviously with the increase of temperature and compressive stress.AE42 alloy enters the accelerated creep stage quickly and exhibites creep rupture character along grain boundaries under the conditions of 175 ℃(398 K) and 100-112 MPa.The compressive creep constitutive equation of AE42 alloy is written as s=8.19×10-7σ5.39exp(-90 410材料2015-05RT),the mechanism of dislocation climb determined by grain boundary diffusion is the main compressive creep mechanism.