Enhancement effect of polyurea coating on the impact resistance of aluminum foam

Abstract A polyurea coating was prepared to enhance the impact protection performance of aluminum foam, and its mechanical properties were analyzed. Polyurea‐coated aluminum foam composite specimens were prepared by coating the polyurea on the surface of aluminum foam. The mechanical properties of composite specimens under quasi‐static and dynamic loading were tested, and the stress–strain relationship at different strain rates was analyzed. The deformation process and failure mode of typical specimens under different loading conditions were discussed. The influence of polyurea coating on the energy absorption characteristics of aluminum foam was explained. The results show that when the polyurea is coated on the end surface of aluminum foam specimen, the sawtooth oscillation in the yield plateau stage of the stress–strain curve is weakened. The existence of polyurea coating makes the stress transfer of cell wall of aluminum foam uniform, and can effectively prevent the damage caused by the splash of aluminum foam fragments under high‐speed impact load. Coating polyurea on the opposite to load‐receiving surface of aluminum foam specimen can effectively improve the yield stress of composite specimen under dynamic load, and make the specimen still maintain good integrity after failure. When the polyurea is coated on the end surface of aluminum foam specimen, the final energy absorption per unit volume and the ideal energy absorption efficiency peak of the specimen are improved.