Compressive performance and deformation mechanism of the dynamic gas injection aluminum foams

Highlights: • The bulk aluminum foams prepared by the dynamic method have porosities of 75 % ~ 95 % and plateau stresses of 0.3-11 MPa. • The dynamic gas injection aluminum foam has better mechanical properties compared to that prepared by static method. • The plateau stress of the aluminum foam with the uniform cell size of around 1 mm could reach up to 22 MPa. • Two main failure modes for cell walls of the aluminum foams: the fracture after plastic buckling and the direct fracture. -- Abstract: The dynamic gas injection method with high-speed horizontal oscillation could reduce the cell size and improve the cell quality of aluminum foams, so it is of interest to study the compressive performance and deformation mechanism of the foams produced with this process. In-situ compression in X-ray tomography was used for this research. Results have shown that the plateau stresses of bulk aluminum foams prepared by the dynamic gas injection method are in the range of 0.3–11 MPa. When the cell size is reduced to around 1 mm, the plateau stress could reach 22 MPa. In addition, the brittle deformation characteristics of the aluminum foams in the quasi-static compression process are obvious. The dynamic gas injection method could greatly improve the mechanical properties of aluminum foams, and aluminum foams prepared by this method have a better compressive performance compared to that prepared by static method even with the same relative density. The uniformities of the cell size and sphericity also affect the mechanical properties. The result of in-situ compression shows that there are two main failure modes for cell walls of aluminum foams: the fracture after buckles of the cell walls and the direct fracture of the cell walls. The aluminum foams prepared by the dynamic gas injection method could have a wide application prospect due to its superior compressive performance.