Development of a formulation to describe the work softening behaviour of magnesium sheets for heated deep drawing processes

Experimental investigations at the Institute for Metal Forming and Metal Forming Machine Tools (IFUM) demonstrate that magnesium sheets possess excellent formability, if the process is conducted at higher temperatures. The investigations are concentrated on improving the forming behaviour of commercial magnesium alloys. For the understanding of the forming behaviour of these materials a detailed evaluation using tensile tests conducted at elevated temperature is required. Because the flow stress decreases with increasing straining, which is represented by the so-called work softening, no appropriate material formulation is available. Furthermore, deep drawing tests with a locally different temperature distribution in the die and blank holder show an additional extension of the forming limits of magnesium sheet material. The obtained results lead to the conclusion that for certain applications it is possible to substitute conventional aluminium and steel sheets by using magnesium sheet metal wrought alloys.