Co-Extrusion of Aluminium-Titanium-Compounds

The combination of different metallic materials enables the design of lightweight structures with tailor-made properties at global as well local scale and offers great potential for advanced solutions especially for the aircraft and automobile sector. Whereas titanium alloys show particular high mechanical strength and good corrosion resistance, aluminium alloys provide a considerable lower density and consequently higher potential for weight savings. However, after conventional fusion joining, e.g. after laser beam welding, heat affected zones, porosity or grain growth may occur and impair the local properties [1, 2]. In contrast, by solid-state joining techniques like co-extrusion these disadvantages can be avoided. Therefore co-extrusion exhibits an attractive solution for long products combining aluminium and titanium based alloys. Current investigations have been focused on the co-extrusion of aluminium and titanium, where titanium is the reinforcing element that is inserted in aluminium profiles. Two different billet variants were examined in the investigations, a titanium-core integrally moulded in the aluminium-billet and titanium-core inserted in a hollow drilled aluminium-billet. Experiments were made with different material combinations, A199.5 with titanium grade 2 and AlSi1MgMn with Ti6A14V. Beside mechanical properties of compound the formation of bonding zone are presented.