Relationship between porosity and interface fracture on aluminum foam sandwich with dense steel face sheets fabricated by friction stir processing route

An aluminum foam sandwich consisting of an aluminum foam core with two dense metallic face sheets is expected to be used as a lightweight structural component with good energy and vibration absorption properties. In this study, by the friction stir processing route, aluminum foam sandwiches with porosity of approximately 5585% and metallurgical bonding between the aluminum foam and dense steel sheets were successfully fabricated. Moreover, tensile tests were carried out on the fabricated aluminum foam sandwiches. Through the test results, it was shown that, although a brittle intermetallic compound layer exists at the interface, fracture in the aluminum foam part with porosity above 65% occurs and the bonding strength of the interface is higher than the tensile strength of the aluminum foam.