The AlCu cast-alloys are of great interest when it comes to high-strength lightweight construction materials. The possibility of precipitation hardening in combination with the low density result in a high specific strength. To further improve the lightweight potential of these alloys, it is possible to combine this material with an open-cell foam structure to provide an even higher specific strength due to the reduction of the solid body content. Applications of interest for this structured material range from lightweight construction, crash absorbers in the transportation sector to heat conducting components such as heat exchangers. To make them accessible to structural applications, their elasto-plastic deformation behavior has to be evaluated. The deformation behavior is well known for pure Al and other Al alloys in the structure of closed-cell foams. The usage as an open-cell foam still provides an open field for research.
This investigation presents a parametric study on the compressive behavior as a function of AlCu foams subjected to different heat treatments. The foam material is produced by an investment casting process with an adaptable relative density ρrel between 2 and 25 %. The pore densitites ρP of these foams range from 7 to 15 ppi. To obtain a holistic understanding of the influence of heat treatment on the compression behavior as-cast condition (F), soft-annealed condition (O) and precipitation hardened condition (T6) are applied. The deformation behavior is analysed under quasi-static conditions to gain information about plateau stress, energy absorption and Young’s modulus. Fracture and deformation behavior analysis are supported by SEM. The results promote further understanding of the relationship between heat treatment, foam morphology and stress-strain behavior of AlCu as open-cell foams.