Hybrid casting – An investigation into the interface of high-pressure die-cast intrinsic aluminum-PEEK-CFRP hybrid composites

Abstract

Abstract The joining of plastic-based fiber composites and light metals is increasingly becoming the focus of lightweight construction applications. To date, conventional mechanical and adhesive joining techniques are still the predominant means to produce hybrid composites. The aim of this work was to create a hybrid composite of CFRP and aluminum in a novel way using the economic high-pressure die-casting process without the use of additional joining elements. The casting process implies the direct contact of molten metal (AlSi10MnMg) and thermally resistant polyetheretherketone (PEEK) under short-term temperatures of about 700 °C. The material and process parameters lead to a material transition that spatially separates the CFRP and the aluminum while guaranteeing a firm bond with lap shear strengths up to 22 MPa. This work structurally and chemically characterizes the interface between Al and PEEK in the hybrid composite. The results of the TEM investigations into the boundary region between PEEK and the AlSi10MnMg alloy show that both materials are locally joined without gaps. Furthermore, the chemical EDX, XPS and IR spectroscopy results indicate a tendency for the bond to form through the thermal alteration of the polymer and the associated modification of the bonding possibilities in the direct contact area.