Effect of low temperatures on deformation localization in supersaturated Al-Li alloys

Active loading at temperatures 295, 77, and 0.5 K is used to study the para meters of the stretching curve and the plastic deformation distribution in quenched and aged Al-Li alloys with 7.0 and 10.4 at.% lithium. It is shown that for aged alloys, in contrast to quenched alloys, the strength is chara cteristically high, the plasticity reserves are low, and the deformation di stribution (macroscopic sections of deformation localization) is nonuniform , if loading is conducted at room and low temperatures (295 and 77 K). The deformation of quenched and aged alloys under deep cooling (at temperature 0.5 K) is distributed more homogeneously through the samples. The results a re attributed to the influence of low temperatures on the rate of thermally activated processes, controlling the motion of dislocations through impuri ty barriers and the deformation-diffusion dissolution of delta (') precipit ates. (C) 2001 American Institute of Physics.