The Compressive Properties and Deformation Mechanism of Closed-Cell Aluminum Foam with High Porosity after High-Temperature Treatment

As a new type of structurally functional material, aluminum foam is widely used in civil engineering due to its excellent noise and energy reduction, thermal insulation, and fire protection properties. However, systematic research into the mechanical properties, application technology, and specification standards of aluminum foam materials in civil engineering application scenarios is lacking. In this work, a special experimental study on the mechanical properties and deformation mechanism of closed-cell aluminum foam materials in compression after fire was carried out. The mechanism of deformation and failure of closed-cell aluminum foam was revealed, and the variation in the mechanical properties of closed-cell aluminum foam with porosity, and heating temperature were investigated. On the basis of the experimental results, the correlation function between material parameters and material porosity in the Liu–Subhash constitutive model was established through multiparameter regression analysis. Then, an intrinsic structure model of aluminum foam that can consider porosity was proposed. The research results show that (1) the compression deformation process of closed-cell aluminum foam specimens exhibits significant stage characteristics: a quasi-elastic stage of quasi-elastic deformation of the matrix and cell structure → a plateau stage of cell structure destabilization and damage → a densification stage of cell collapse and stacking. (2) As the porosity decreases, the aluminum foam material becomes more resistant to compressive deformation and shows better compressive mechanical properties overall. With an increase in the heat treatment temperature, the elastic gradient, compressive proof strength, and plateau stress of the aluminum foam material show a small decrease in the overall trend. (3) The predicted values of the intrinsic structure model of closed-cell aluminum foam are in good agreement with the experimental results, indicating that the model can efficiently characterize the stress–strain process of the material and is referable.