OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 24 No. 3 2022 boundaries 2, reaching the point of transition from the perforation edge to the welding zone of the composite viscous metal base 4, stop on it and the development of the brittle crack stops. This makes it possible to localize the zone of ballistic destruction of composite armor within the local zone of welding of aluminum and titanium layers 2, preserving the integrity of the product structure and its complex bullet resistance without obligatory replacement with a new armor element. Diagram of brittle crack localization in composite structure at contact with a ballistic object is given in Fig. 4. Fig. 4. Diagram of brittle cracks localization in the composite structure Fig. 5. Dependence of growth of intermetallic layer thickness on furnace holding time In addition, the presence of thin perforated layers in the structure of the metal composite material also contributes to an increase in its strength indicators [17]. Evaluation of strength parameters and preparation of the test samples were carried out according to the standard method in accordance with GOST 1497–84. A set of studies has shown that the best combination of physical and mechanical properties, such as strength and elongation, is possessed by samples welded at the selected rational mode. Its relative elongation was from 3.1 to 3.7 %, and the strength value was in the range from 570.2 to 594.1 MPa. Provided that the strength of the composite metal matrix base of similar thickness was in the order of 482.1–489.8 MPa, the total increase in the strength of the composite compared to it was 21.3 % [18, 20]. In order to improve the tactical and technical characteristics of the composite armor materials being developed on the basis of light metals and alloys, the authors proposed the formation of highsolid intermetallic layers in the composite structure due to heat treatment. Intermetallic layers are formed due to mutual thermal diffusion of metals included in composite at interlayer boundaries. Maximum thickness of intermetallic layers is controlled by parameters of heat treatment, namely temperature and time of soaking during annealing. A set of studies made it possible to establish the dependence of the growth of the intermetallic layers thickness on the soaking time; the results are shown in Fig. 5. Analysis of the obtained data indicates that the maximum thickness of the intermetallic layer is approximately 90–100 μm, while the holding time at a temperature of 625°C is approximately 300 hours.
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