Thermal stability of high-deformed nonmetallic crystals under static annealing


I. M. Frantsevich Institute for Problems of Materials Science of the NAS of Ukraine, Krzhizhanovsky str., 3, Kyiv, 03142, Ukraine
Electron Microscopy and Strength of Materials - Kiev: Frantsevich Institute for Problems of Materials Science NASU, 2016, #22


The results of comparative electron microscopy investigation for the substructure in crystals (grains) of two types of polycrystalline samples from powders of the covalent substances 6Н- and 3СSiC, AlN as well as TiB2 are presented. The samples were compacted under high pressures of quasi-hydrostatic and shock compression alongside with annealing in the initial state and after static heating under ambient pressure. It has been established that the starting temperature for recovery of deformed substructure in the crystals depends on the deformation conditions whereas the structural mechanisms of the recovery are connected to the type of deformed substructure, which is defined by the peculiarities of the lattice deformation. Generally, defective substructure recovery in the studied materials is accompanied by decrease in the effective and real grain size, which occurs due to rearrangement of dislocations and primary recrystallization. Full text download