Mechanism of microplasticity at indentation in diamond-structure crystals at low temperatures

The mechanism of creating a stable print at microhardness indentation in diamond-structure crystals is discussed, in which dislocations are quite immobile at room temperature. It is argued that this mechanism consists in the generation of prismatic dislocation loops in the under-indenter region and subsequent removal of the loops from this region, due to a special kind of dislocation motion called conservative climb. A simplified analytical model of such a process is presented and according to that model certain numerical values and dependences associated with microhardness measurement are estimated and compared with those found experimentally for Ge.