Effect of micro-cracks on mechanical and damping properties of double-layered Al/Al plate

To investigate the influence of micro-cracks (including formation and growing) on mechanical and damping capacity, the grooved (with two dimensions) and non-grooved Al plates were subjected to cold roll bonding (CRB). Microscopic morphology, tensile and damping test of the experimental materials were investigated. Due to uneven stress distribution, the edges of grooves were heavily inclined in the normal direction (ND), and the grooves were changed into micro-cracks with the sizes of a few to a dozen microns. Mechanical properties of the Al sheet with micro-cracks were decreased, which further lowered with micro-cracks growing. There were two internal friction peaks for the Al sheet with micro-cracks, which mainly attributed to the stronger local stress and local plastic deformation around the micro-cracks.