Effect of electron irradiation on the strength of niobium single crystals

The effect of electron irradiation on the plastic deformation of niobium single crystals was investigated at temperatures between 4.2 K and 77 K. Two different tensile axis orientations were chosen, i.e., one at the center of the standard triangle (designated as C) and the other on the /100/-/111/line, 45 degrees from the primary Burgers vector (designated as H). The C crystal deformed by the anomalous slip and the H crystal deformed by the primary slip. A significant difference in the deformation behavior between C and H crystals without irradiation is described. The effect of room temperature prestraining on the two crystals is discussed.