Operative slip systems and anomalous strengthening in Ni3Nb single crystals with the D0a structure

The plastic deformation behavior of Ni3Nb single crystals was examined in tension and compression to determine the operative slip and twinning systems, and to explore the anomalous strengthening behavior. A strong temperature dependence of the CRSS for both the slip and twinning systems was observed, which was dependent on the sample orientation. Anomalous flow behavior was also observed in Ni3Nb crystals deformed by (010)[100] and (001)[100] slip. The anomalous strengthening mechanism is discussed on the basis of both the anisotropy of APB energy and the formation of dragging atmosphere around moving dislocations.