[en] We investigate regularities of the shock wave propagation and fracture in the Al-Cu composite under high-current electron irradiation. A model of multiphase medium mechanics is used, which takes into account the finite rate of stress relaxation between phases, the heat transfer, and the relative motion and friction between components. The multiphase medium model is supplemented by the models of plasticity and fracture. The presence of inclusions in the matrix significantly influences the generation and propagation of stress waves in the irradiated target. In addition, molecular dynamics calculations of tensile strength are performed, which show that the presence of copper inclusions reduces the strength of the material. The reason for softening is the stress concentration near the inclusion, rather than the weak adhesion between copper and aluminum. (paper)