Creep behavior and microstructural evolution of 8030 aluminum alloys compressed at intermediate temperature

Abstract

The compression creep behavior of 8030 aluminum alloys at intermediate temperature was studied under the deformation temperature of 200∼250 °C and compression stress ranging from 20 to 40 MPa. The apparent stress exponent (na), the true stress exponent (nt) and the activation energy Qc for creep were na = 3.6, nt = 3 and Qc = 145.5 kJ/mol, respectively, indicating that the dislocation viscous glide controlled by lattice self-diffusion was the dominant creep mechanism of the samples at 200 °C-20 MPa. A creep constitutive equation was introduced with the threshold stress σ0 = 5.1 MPa. The microstructure characterization of selected samples was investigated by transmission electron microscopy (TEM), indicating that the sub-grain contours became ambiguous and the dislocations with long curved morphologies were homogeneously distributed within grain inners after creep for 100h.