Cross-slip patterns by sphere indentations on single crystal MnZn ferrite

The experiments on the deformation of crystals of MnZn ferrite by indentation with a loaded sphere are extended to (111) planes. As shown before on (001) and (110) planes the deformation consists of coupled slip lines. The slip patterns are discussed in terms of the possible slip planes for a Burgers vector along 〈110〉. A complete description is given on the assumption of cross slip between the slip systems, {110}, {111} and {100}. The analysis is supported by calculations of the resolved shear stress (RSS) on the basis of the elastic equations for a halfspace loaded by a sphere. The source of dislocations is located where the RSS is largest. On the assumption that propagation of slip is easier than nucleation, several cases of coupled slip (“pencil glide”) are considered. A check on the model is made by calculating the length of the slip lines on the surface between the start and the cross-over. The experimental data show a wide spread, but on the average they agree with the model. {100} and {111} appear as primary slip systems when the RSS is sufficient. {100} is excited only in cross-slip, at about the same RSS values as for {100} and {111}. The RSS where propagation stops, show a wide spread too, 0.6–1.8 GPa, but the lowest minimum is found for {100}.