On the yield anomaly in stoichiometric CoTi

Compression tests performed on stoichiometric CoTi polycrystals over a range of temperatures and strain rates from 5×10−6 to 1 s−1 show a positive temperature dependence of the yield stress before a decline at elevated temperature. This yield strength peak shifts to higher temperatures with increasing strain rate. At temperatures close to that of the peak yield stress, serrated yielding and a negative strain-rate sensitivity of the yield stress occur. Static strain-aging is also observed. These observations are consistent with strong solute–dislocation interactions and suggests that the anomalous yield behavior of CoTi is a manifestation of dynamic strain-aging.