TY - JOUR

T1 - Development of an aluminum-based hybrid billet material for the process-integrated foaming of hollow co-extrusions

AU - Schäfke, Florian Patrick

AU - Thürer, Susanne Elisabeth

AU - Maier, Hans Jürgen

AU - Klose, Christian

N1 - Funding Information: Funding: This research was funded by the German Research Foundation (DFG) through the project “Aluminium alloys with controlled melting ranges for process-integrated foaming during extrusion”, grant number 324394568. The publication of this article was funded by the Open Access Fund of the Leibniz Universität Hannover.

PY - 2021/8/31

Y1 - 2021/8/31

N2 - Metal foams are attractive for lightweight construction in the automotive sector since they provide high-energy absorption and good damping properties, which is crucial, e.g., for crash structures. Currently, however, foams are produced separately and then pasted into the components. Consequently, the overall mechanical properties depend significantly on the quality of the adhesive bond between the foam and the structural component. A new process route for the manufacture of hybrid foamed hollow aluminum profiles is proposed. In this approach, a foamable precursor material is directly integrated into the extrusion process of the hollow structural profile. To this end, special low-melting alloys were developed in this study to enable foaming inside the aluminum pro-file. The melting intervals of these alloys were examined using differential scanning calorimetry. One of the promising AlZnSi alloys was atomized, mixed with a foaming agent and then compacted into semi-finished products for subsequent co-extrusion. The foaming behavior, which was investigated by means of X-ray microscopy, is shown to depend primarily on the mass fraction of the foaming agent as well as the heat treatment parameters. The results demonstrate that both the melting interval and the foaming behavior of AlZn22Si6 make this particular alloy a suitable candidate for the desired process chain.

AB - Metal foams are attractive for lightweight construction in the automotive sector since they provide high-energy absorption and good damping properties, which is crucial, e.g., for crash structures. Currently, however, foams are produced separately and then pasted into the components. Consequently, the overall mechanical properties depend significantly on the quality of the adhesive bond between the foam and the structural component. A new process route for the manufacture of hybrid foamed hollow aluminum profiles is proposed. In this approach, a foamable precursor material is directly integrated into the extrusion process of the hollow structural profile. To this end, special low-melting alloys were developed in this study to enable foaming inside the aluminum pro-file. The melting intervals of these alloys were examined using differential scanning calorimetry. One of the promising AlZnSi alloys was atomized, mixed with a foaming agent and then compacted into semi-finished products for subsequent co-extrusion. The foaming behavior, which was investigated by means of X-ray microscopy, is shown to depend primarily on the mass fraction of the foaming agent as well as the heat treatment parameters. The results demonstrate that both the melting interval and the foaming behavior of AlZn22Si6 make this particular alloy a suitable candidate for the desired process chain.

KW - Extruded aluminum profiles

KW - Metal foam

KW - Process-integrated foaming

KW - X-ray microscopy

UR - http://www.scopus.com/inward/record.url?scp=85114089204&partnerID=8YFLogxK

U2 - 10.3390/met11091382

DO - 10.3390/met11091382

M3 - Article

AN - SCOPUS:85114089204

VL - 11

JO - Metals

JF - Metals

SN - 2075-4701

IS - 9

M1 - 1382

ER -