Laves phase strengthening in ultrafine-grained Co–Cr–Ta micropillars under uniaxial compression at modest temperature

Abstract

The substantial reduction in strength has limited the widespread usage of Co–Cr based alloys at elevated temperatures. Here, we designed and fabricated an ultrafine-grained Co–28Cr–3Ta alloy which could retain over 80% of its room temperature yield strength at 300 °C, two times that of its equivalent without addition of Ta. Such high thermal stability was achieved via a processing route which precipitated nanoscale Laves phases. The results demonstrate that Orowan strengthening operates as the dominant mechanism in the alloy. The dislocation loops formed from interactions between dislocations and precipitates could effectively prevent the dislocation gliding at modest temperature.