Compression Behavior of Low-Pressure Cast AMC Syntactic Foams with High Porosity

This work presents a method for the manufacturing of closed-cell aluminum matrix composite syntactic foams (AMCSFs) using a modified and simplified low-pressure infiltration setup. The influence of different wrought and cast alloys on the compressive behavior of these foams was investigated. Through the use of a variety of different cast and wrought alloys, it was possible to determine the Al matrix’ influence on the compressive behavior. The investigated AlX-Al₂O₃ syntactic foams were manufactured using hollow alumina spheres with AA1050, AA2024, AA5019, AA7075, and A356 Al alloys in the as-cast state. The results of the manufacturing process and the selected process parameters show a good dispersion of the spheres within the AlX matrix with a typical near randomly close-packed structure at the same time. The high-strength Al alloys AA2024 and AA7075 lead to a very brittle deformation behavior of the foams in the compression tests, with a strongly oscillating behavior plateau and relatively low plateau stress level. In contrast, the low- and mid-strength alloys AA1050, AA5019, and A356 show a more ductile behavior with less oscillation at a higher plateau stress level. By the five different combinations of the material partners, it was possible to make a statement about the ductility–strength relation of metallic syntactic foams in dependence on the base matrix.