Multilayer composite materials, consisting of layers of aluminum alloy and steel, are used in the manufacturing of large engineering structures, including in the shipbuilding and railcar industries. Due to the different properties of aluminum alloys and steels, it is difficult to achieve high-strength joints by conventional welding. Therefore, these joints are produced by explosive welding. In the present work, the structure of a multilayer material, AA1070-AlMg6-AA1070 (aluminum alloys)-VT1-0-08Cr18Ni10Ti (steel), was investigated after explosive welding and heat treatments were performed under different conditions. The microstructure of the AlMg6 layer at the AlMg6-AA1070 interface consists of shaped anisotropic grains extending along the weld interface. The AA1070 layer is enriched with magnesium due to its diffusive influx from AlMg6. In the AlMg6 and VT1-0 layers, adiabatic shear bands are found that start at the weld interface and propagate deep into the material. The optimal temperature for the heat treatment is 450–500 °C, as internal stresses are reduced at this temperature and the grain structure of the AlMg6 layer is not coarse. Tear strength testing revealed that the tear strength of the composite material after explosive welding was 130 ± 10 MPa, which exceeded the strength of the AA1070 alloy.

This paper presents the aspects of the formation of multilayer composite material (MCM) consisting of aluminium-magnesium alloy AlMg6, titanium VT1-0 and austenitic stainless steel 12Cr18Ni10Тi during explosive welding. This MCM has promising properties for use in various industries such as shipbuilding and automobile manufacturing. However, the production of this material presents certain difficulties due to different properties of the initial materials. In this paper, the effect of residual stresses occurring in MCM after explosive welding on the continuity of the joint was investigated. Using metallographic studies and electron microscopy, it was found that the high velocity impact process between different materials comprising MCM formed weld interfaces with straight and wavy profiles. There was also evidence of dynamic recrystallisation at the 12Cr18Ni10Ti–VT1-0 weld interface and the formation of vortex zones in wave crests. The microhardness of the layers was also measured. The measurement showed that hardening occurred in MCM layers with the maximum value in the 12Cr18Ni10Ti steel layer. The evaluation of tear strength revealed that the formation of cracks occurred at the interface between the VT1-0–AlMg6 weld interface, with an average strength of 160 MPa. The results of the study may be useful to specialists in materials science, mechanical engineering and other related fields