Dislocation Exhaustion and Stress Anomaly in L12 Alloys: The `E.L.U.' Model
Résumé
A statistical model is proposed to account for strength anomalies in L12 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.
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