Interfacial strength analyses of Al/Mg compounds using bending tests

Abstract

In the Collaborative Research Center 692, subproject B3 Al/Mg compounds are investigated. The hydrostatic co-extruded compounds presented in this paper were further manufactured by the forging process Rising. To continue the first investigations of Rising specimens regarding interface strength, a bending test developed in a previous project period was used. The specific load case and the bending specimen geometry considers the requirements concerning the special geometry of the Rising specimen. Based on experimentally determined failure forces (maximum forces), the stress state for the investigation of the interface strength was calculated by means of the elementary bending theory extended with a numerical determined correction factor. The numerical analyses were based on a parametric FE model of the load case. Crack initiation was caused by the maximum interlaminar interfacial tension stress. In the demonstrated investigations co-extruded compounds with different ratio of core material (Mg) in the transversal cross sectional area of the initial billet were analyzed. A particular feature of the investigations is the interfacial strength analysis of a subset of Rising specimens in different areas of the transversal cross section. This was enabled by using compounds with larger sleeve thickness due to a lower Mg ratio. Thus, in this case a more extensive characterization could be performed. The results show higher strength values for Rising specimens with the largest sleeve thickness compared to the other investigated configurations.