Aluminum matrix composite extrusions reinforced with wires made of high strength stainless steel represent an innovative material concept for lightweight structures. The use of reinforcing elements should improve the mechanical properties and the performance of lightweight structures. This study deals with the process chain of extrusion and die forging to manufacture steel-reinforced products. The production of discontinuously-reinforced, semi-finished aluminum profiles by co-extrusion is in focus on the extrusion part. The material flow is analysed in order to understand, and further to influence, where the steel-reinforcements are appear in the strand. For the forging part the extruded profiles are continuous-reinforced by means of steel wires as well as partially by means of steels elements. For the process design the geometry of the forging die cavity and the material flow are of vital importance. A Finite Element Analysis is carried out in order to predict the position of the elements in the forging parts depending on the position in the extrusions.

Abstract.A promising approach to handling low ductile aluminium alloys in a forming process is forming under superimposed hydrostatic pressure. The influence of superimposed hydrostatic pressure on the flow stress as well as on the formability for various hydrostatic pressures and temperatures was analysed [15, 3, and 7]. By increasing the formability of the workpiece, larger local plastic strains could be achieved. The results reveal highly increased formability at superimposed pressure of 85 MPa for workpieces from thermosetting alloy AlSi1MgMn (EN AW-6082) in comparison to those from self-hardening alloy AlMg4.5Mn0.7 (EN AW-5083). As a general tendency, the self-hardening alloys show a lower increase in formability when forged under superimposed pressure. But additionally, a charge-dependent influence of macro-and micro defects on the crack resistance was detected for alloy AlMg4.5Mn0.7. By evaluating damage models in finite element models the damage occurring in cold forming processes under superimposed hydrostatic pressure was predicted.

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