Feasibility of high-strength 7xxx aluminium sheet components through warm forming

High-strength 7xxx-series (AlZnMgCu) aluminium alloys are already widely used in aircraft construction and offer a great potential for further light weighting in automotive body-in-white, but formability at ambient temperature is severely limited without the employment of pre- and post- forming heat treatment processes. A promising approach to improve the formability of the 7xxx aluminium alloys is to utilize warm forming at process temperatures below the material´s recrystallisation temperature. FEM simulations verified by warm drawing experiments of high-strength aluminium sheet 7075-T6 show the feasibility of forming complex deep drawn components. Using a cross-die, the effect of the temperature on the drawing depth and the mechanical properties is investigated. Initial resistance spot welding (RSW) experiments of this difficult to weld alloy are also promising.