Effect of the Cu addition on the mechanical properties and microstructure of open-cell Al foams

Aluminum (Al) and Al–4.5Cu wt% open-cell foams were produced by the replication casting technique in two different pore sizes, avoiding subsequent heat treatments. All produced samples were physically characterized by means of He pycnometry. Microstructural and chemical analyses were carried out using scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and image processing techniques. Uniaxial compression tests were conducted, with the aim of generate the stress–strain curves of the Al and Al–4.5Cu wt% foams. It was found that plastic collapse and plateau stresses increased from ~ 3 and ~ 12 MPa to ~ 10 and ~ 30 MPa, while the energy absorption capacity of the Al–4.5Cu wt% foams was almost trebled regard the pure Al foams. These outcomes were attributed to the formed microstructure, constituted by dendritic arrangement of α-Al (~ 57 HV) and θ-Al2Cu (~ 326 HV). Thus, this work gives way to produce mechanically enhanced open-cell Al foams derived from the Cu addition.