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

contaminated with impurities of iron and silicon, and the composition of the alloy becomes multicomponent, since they contain complex compounds. Figure 9 shows an alloying phase particle in the aluminum alloy. The complex structure of intermetallic particles is determined by a specificity of the heat treatment of the material. The heating temperature for hardening is selected from the condition of maximum dissolution of the strengthening phases: at these temperatures, iron-based intermetallic compounds remain in the solid state, and during cooling they become centers of crystallization of soluble intermetallic compounds, which form a rim with an enhanced copper content. Solid solutions in all hardened duralumins are highly oversaturated with copper, so the rim acquires a bright color due to the fact that the higher the density of the metal, the brighter the image in the rays of reflected electrons. Figure 9 shows that almost all initial particles contain a light iron core surrounded by a bright copper rim. Figure 10 shows the LSBs microstructure near the region of spall crack transition into the localized strain band. In this case, the high-velocity tension stress is close to the dynamic strength of the material, and this is the maximum possible tensile value at which the continuity of the material is maintained. The microstructure of LSBs consists of a highly deformed material with a large number of micropores, whose size varies from 100 to 400 µm. This pattern is typical of all materials studied (titanium, steel). The phase composition of intermetallic compounds in the LSBs underwent changes. The alloying phase particles retain the rim, but its color becomes light, i.e., close to the color of the base alloy. The iron-containing core becomes brighter than the rim indicating that the copper rim has dissolved. Small soluble intermetallic compounds 0.5–2 μ m in size, which in the original alloy had the shape of irregular polygons, acquired rounded outlines. The number of particles in the LSBs with a size less than 500 nm has increased noticeably compared to the undisturbed material, which indicates the partial dissolution of intermetallic compounds in the LSBs. c) Migration of particles to places of spall damage (self- healing effect) Damageability of Metals under Impulse Loading 1 Year 2023 29 Frontier Research Volume XXIII Issue ersion I VXI ( A ) Science © 2023 Global Journals Global Journal of Fig. 9: Initial microstructure of alloying phase particles in the aluminum alloy. Fig. 10: Microstructure LSBs of duralumin in the zone of transition of the spall crack into the strain localization band. Alloying additives in the dispersion- strengthened aluminum alloy under consideration were arranged in a row in the form of colonies formed during technological rolling. The distance between the colonies of intermetallic compounds varied within 15–40 µm, and the individual particle size of the strengthening phase was 0.5–2 µm. Figure 11 shows LSBs in the aluminum alloy with particles of intermetallic compounds accumulated at the boundaries. Particle segregation indicates the migration of alloying phase particles from the adjacent matrix region to the spall damage sites. The thickness of the layer, where intermetallic compounds are practically absent and from where they migrate to damaged areas, is 5-10 µm sometimes reaching 20 µm [32]. Figure 12 shows the microstructure of the LSBs in the two-phase titanium alloy. The initial ( α + β ) structure of the titanium alloy is plate-like. Inside the β - phase, colonies are formed from parallel plates of the α - phase (thickness 0.2 – 0.7 μ m, length 5 – 8 μ m) similar in appearance to pearlite colonies in steel. The average distance between the colonies is about 2 μ m. Darker areas near the LSBs depleted of α -phase particles do not exceed 3–5 μ m and are not localized along the entire length of the LSBs.