Hall-petch relationship in an Al-Mg-Sc alloy subjected to ECAP

Abstract

Effect of extensive grain refinement on mechanical properties of an Al-Mg-Sc alloy subjected to equal-channel angular pressing (ECAP) at 300°C is considered in detail. It was shown that the Hall-Petch relationship with the coefficient, ky, of 0.2 MPa×m1/2 is valid in a wide strain range despite a great difference in deformation structures. Volume fraction of fine grains with an average size of ~1 μm gradually increases with strain. It is caused by the fact that additive contributions of grain size strengthening and dislocation strengthening to the overall strengthening take place in this alloy. Upon ECAP the extensive grain refinement is accompanied by increasing dislocation density