Influence of rest on mechanical properties of GaP single crystals deformed by scleroscopic method at different temperatures

Abstract

The areas of the GaP (111) plane placed between the scratches parallel to [110] have been investigated. The deformation degree of these areas was varied by distance between scratches (60-180 µm) and scratching temperature (T = 20, 150, and 450°C). It was obtained that the microhardness value (H) is smaller and the acoustic emission (AE) is more intensive for the areas with higher stress state. It was established that rest (~500 h) resulted in the AE significant increase for complete cycle of microindentation and emission in unloading. It was shown that the active formation of cracks and, especially, a material break off around the indents under microindentation of the investigated GaP zones have been observed while the AE increase; however, the H value in this case changed weakly. Obviously, after rest the revealed deformation acts differently influence the AE and microhardness changes. The essential changes of the relaxation coefficient (K) dependence on deformation degree as a result of rest have been revealed: K linearly increases with deformation degree increase before rest and monotonically decreases after rest.