Mechanical characterization of AISI 316 tubes filled with Al alloy foams

In tubular elements filled with metal foams the structural collapse is delayed in comparison with the empty tubes, consequently compression strength and absorbed energy increase. Production methods of foams are crucial, as they determine cellular morphology and bonds formation with tube wall. In this work AISI 316 steel tubes filled with foam of commercially pure Al and Al-Si alloys with hypoeutectic compositions were produced. The process parameters were optimized to obtain closed cells foams with an acceptable morphology of porosity and good mechanical properties. Foams were characterized by optical and scanning electron microscopy and by computer tomography; mechanical properties were investigated by axial compression tests (performed on foam samples and on Cu tubes, empty or filled with foams) and radial compression "Brazilian test" (carried out on AISI 316 tubes, empty or filled with foams).