Room temperature deformation in the Fe7Mo6 μ-Phase

The role of topologically close packed (TCP) phases in deformation of superalloys and steels is still not fully resolved. In particular, the intrinsic deformation mechanisms of these phases are largely unknown including the active slip systems in most of these complex crystal structures. Here, we present a first detailed investigation of the mechanical properties of the Fe7Mo6 mu-phase at room temperature using microcompression and nanoindentation with statistical EBSD-assisted slip trace analysis and TEM imaging. Slip occurs predominantly on the basal and prismatic planes, resulting also in decohesion on prismatic planes with high defect density. The correlation of the deformation structures and measured hardness reveals pronounced hardening where interaction of slip planes occurs and prevalent deformation at pre-existing defects.