Pseudotwinning in indium-lead concentrated alloys

Abstract

Pseudoelasticity caused by pseudotwinning in short-range ordered In-Pb alloys (6, 8 and 11.6 at.% Pb) is studied in the temperature range 1,7-180 K. The mechanical hysteresis parameters, namely, the thermodynamic stress τ T which provides the reversibility of plastic deformation and the friction stress τ f which characterizes the resistance offered by crystal lattice and its defects to twin boundaries motion are estimated. It is found that athermal processes determine the reversible deformation; the mechanical parameters τ T ? τ f do not depend on temperature and strain rate. The stress τ T increases and the stress τ f decreases with increasing Pb content. One of the main conditions of the exhibition of superelasticity is the fulfillment of the inequality τ T >τ f .