Dislocation Density and Internal Stress in an Al-5.7 at%Mg Alloy

Abstract

In order to investigate the origin of internal stress in a solution-hardened temperatures, the internal stress and dislocation density have been simultaneously determined by a stress change test during creep deformation of Al-5.7 at%Mg alloy in a temperature range 573–673 K and a stress range 4.5–40 MPa.It is found that a unique relation,\barσi=0.37Gb\sqrtρ,holds whether the creep is in a steady state or not, where \barσi is the internal stress, ρ the dislocation density, G the shear modulus and b the magnitude of the Burgers vector. From the relation, it is concluded that the origin of internal stress is the long range stress field of forest dislocations.