Deformation behavior and spalling fracture of a heterophase aluminum alloy with ultrafine-grained and coarse-grained structure subjected to a nanosecond relativistic high-current electron beam

The results of a comprehensive experimental–theoretical investigation of the deformation behavior, regular features and mechanism of spalling fracture in an Al–Mg–Li–Zr heterophase aluminum alloy with ultrafineand coarse-grained structure subjected to a nanosecond high-current electron beam with the power density 7·109 W/cm2 are presented. The patterns of formation and propagation of a shock wave are discussed, and so is the behavior of the respective reflected wave, once the former is reflected from the back surface. Common regularities of variation in the thickness of the spalled layer and its plastic deformation degree are observed in the cases of ultrafine- and coarse-grained structure. It is shown that spalling resistance of the Al–Mg–Li–Zr heterophase alloy is controlled by the ultrafine-grained structure formed in the spalling zone under the tensile wave rather than by the initial grain structure.