Global Journal of Science Frontier Research, A: Physics and Space Science, Volume 23 Issue 11

a b Fig. 13: Microstructure of steel 3 in the localized strain band. The impactor plate was accelerated by the charge of 6ZhV ammonite (a), area with crushed cementite plates (b). An increase in the load amplitude above 15 GPa changes the microstructure in the LSBs of the steel sample: almost all pearlite transforms into the globular form, which is clearly seen in Fig. 14. In this case, cementite globules can reach a size of 2-3 μ m. It is characteristic that the material exists in the porous state near the internal boundary of the LSBs . Microspectral analysis showed the presence of a high carbon content, while in the spherical globule of cementite itself the carbon content corresponds to the formula of the metastable phase Fe х C, where х < 3. Fig. 14: Microstructure of steel 3 in the region of transition of the spall crack into the localized strain band; the impactor plate was accelerated by a charge of cast TNT. Damageability of Metals under Impulse Loading 1 Year 2023 3 Frontier Research Volume XXIII Issue ersion I VXI ( A ) Science © 2023 Global Journals Global Journal of Energy dispersive analysis of the steel sample to carbon revealed a layer near the LSBs 20-40 µm thick depleted of carbon and a very thin layer directly adjacent to the LSB enriched in carbon. The high carbon content in LSBs was noted in [36]. Microhardness measurements [4] made it possible to identify areas with reduced microhardness 50 µm thick at both sides of the localization band , while the band itself exhibited increased microhardness. Microhardness in steels depends on the carbon content and varies almost linearly decreasing by approximately 80 units for every 0.15% (by weight) decrease in the carbon content [37]. The presence of a depleted layer indicates mass transfer of carbon from the adjacent zone of the matrix material to the damage area. The supply of carbon atoms from the matrix to the LSB zone increases the carbon content in the localization band itself, which explains the transition of all pearlite to cementite. The migration of alloying elements and dissolution of interstitial and substitution phases are well-known for quasi-static cold deformation [38, 39].The activation of low-temperature dissolution of intermetallic compounds is achieved due to the generation of a large number of point and linear defects