抄録
Single crystals of iron with the [110] and [410] axes were fatigued in push-pull at constant total strain amplitudes in the range between 0.1 and 2%. When the strain amplitude was smaller than 0.5%, the cyclic hardening of the [410] crystal was similar to that of the [110] crystal. Clusters of edge dislocation dipoles and loops were developed parallel to the {112} slip plane, which suggests the activation of single slip locally. When the strain amplitude is larger than 0.5%, the cyclic hardening of the [410] crystal was much larger than that of the [110] crystal. Cell walls lie along symmetry planes with respect to the slip planes, which suggests multiple slip. Striation patterns on the fracture surfaces appeared parallel to the intersection between operative {112} slip planes in both crystals. When a crack was forced to propagate to perpendicular to the slip vectors, in the [\bar110] direction on the (110) plane, it propagated in the ⟨332⟩ directions with a deviation of 40 degrees from the [\bar110] direction.
