A. V. Dobromyslov, N. I. Taluts

AN ELECTRON-MICROSCOPIC STUDY OF THE DEFORMATION STRUCTURE OF THE 12Kh18N10T STEEL AFTER EXPLOSIVE LOADING IN SPHERICAL SYSTEMS

Optical metallography, transmission electron microscopy and microhardness measurements are used to investigate the deformed structure of retained shells made of the 12Kh18N10T steel after explosive loading. It has been established that the high-rate plastic deformation of the steel under this loading occurs both by slipping and twinning. It is shown that there is a strong localization of deformation resulted in the formation of rough traces of slip. The high pressure at the shock wave front results in the fact that the critical shear stress in one grain is achieved in several slip systems simultaneously, irrespective of the Schmid factor. Therefore, several nonequivalent systems become active slip systems at once. Microtwins form large clusters in which they mainly belong to one or two systems of twinning. The average thickness of microtwins is ~ 30‒40 nm. Polymorphic γ → α transformation has been revealed under explosive loading. The α-phase is observed in the form of fine precipitates. It has been found that the microhardness almost doubles after shock loading, as compared with that of the initial state.

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