We consider problems on interaction between high-speed strikers and obstacles protected by special functionally gradient layers. Strikers and obstacles are made from iron. A protecting layer is an alloy of iron and aluminum such that the ratio of volume fraction varies linearly. We study the influence of gradients of physical and mechanical properties as well as porosity of protecting layer on stresses in the obstacle, velocity of its backside, and characteristics of scabbing phenomenon in the system striker-obstacle. We vary physical-mechanical characteristics of the protecting layer as well as its thickness.