Dislocation Exhaustion and Stress Anomaly in L1 ₂ Alloys: The `E.L.U.' Model

(Received 13 February 1995, revised 18 May 1995, accepted 6 July 1995)

Abstract
A statistical model is proposed to account for strength anomalies in L1 ₂ alloys. It is based on a competition between locking of superdislocations into Kear Wilsdorf locks and by-passing these locks by macrokinks. From the statistical distribution of macrokink heights, it is shown that the population of mobile dislocations is exhausted with an increasing efficiency as temperature is raised. This yields either an exhaustion creep at constant applied load, or a strength anomaly in constant strain rate conditions. Several consequences on strain rate sensitivity, work-hardening, or flow stress reversibility are envisaged.