抄録
Effects of oxygen (O) on orientation dependence of critical resolved shear stress (c.r.s.s.) and of active slip plane in Nb, Nb–20Ta and Nb–20Mo single crystals were investigated by compression tests at 298 and 973 K. c.r.s.s. is remarkably increased by O addition. At 298 K, coarse wavy slip lines evidencing macroscopic cross slip are observed in the low O content alloy, while fine straight slip lines are observed in the high O content alloy. Observed slip planes of O-doped Nb and Nb alloys correspond nearly to maximum resolved shear stress planes (m.r.s.s.p.). Orientation dependence of c.r.s.s. is emphasized by O addition in Nb–20Ta at 298 K and in Nb–20Mo at 973 K. From these results, interaction between O atoms and screw dislocations is discussed.
