Critical shear stress temperature dependence in Al?Mg single crystal alloys of various concentrations in the range 1.6?300�K

Abstract

1. The critical shear stress temperature dependence for Al−Mg single crystal alloys and for Al crystals had three regions in the studied temperature range: (a) 300−(120–130)°K, in which the CSS is temperature independent; (b) 120−4.2°K, in which the CSS rises with falling temperature (the temperature T0, above which τ = τG, slightly shifting to lower temperatures side with increasing Mg content in the alloy); and (c) below 4.2°K, for which the CSS decreases with decreasing temperature. 2. The magnitude of the critical shear stress in the studied temperature and concentration ranges is proportional to √c and is described satisfactorily using Fleischer's concepts of edge dislocation interaction with the maximum elastic stress fields and localized shear modulus concentration variations. 3. The absolute fall in the CSS at temperatures below 4.2°K rises proportionally to √c, its relative value not depending on the alloy Mg concentration.