Cell walls often contain high volume fractions of coarse eutectic, fine oxide films and large brittle particles, which can affect both local and global plastic deformation characteristics. There has been substantial progress within the project on the development of improved processing routes for production of metallic foam material and components. Improved understanding has been obtained of the origin and significance of the various ceramic constituents which are commonly present within the cell walls of most types of metallic foam material. Processing approaches being developed have the potential for producing foams with cell walls having low ceramic contents and hence improved toughness. The effective yield strength of constrained foam layers is only marginally greater than the unconstrained uniaxial yield stress.
Predictions are broadly consistent with experimental data.
Multiple cracking, which can be stimulated in laminates made from dense metallic layers, and can have strongly beneficial effects on the toughness, has not been observed with foam laminates. This is consistent with model predictions, which indicate that the strength of the foams currently available would have to be raised substantially in order for multiple cracking to occur. However, this does depend on the loading geometry. Twelve publications have arisen from the project. They are listed on the IGR form and also referenced in this report.