Experimental and Numerical Study on forming limit diagram of two-layer metallic sheets at high temperature

Two-layer metallic sheets are very important Alternative for single-layer metal sheets which have many advantages including weight loss and high strength to weight ratio. Using these sheets saves energy. Hence, the replacement of single-layer metal sheets with two-layer metallic sheets is one of the industry's requirements. One of the most important defects in the sheet metal forming is tearing. Heating of the sheet is one of the ways to postpone the tearing. According to previous studies, there has been no research on warm formability of two-layer metallic sheets. In this research, the aim of the study is to determine forming limit diagram of copper-aluminum two-layer sheets at warm temperature range by experimental and numerical methods. In the experimental method, the formability diagram was obtained by Stretch forming tests with hemispherical punch and Tensile tests. The results of the experimental method showed that with increasing temperature, the formability increases, The maximum deformation force is reduced, also the height of the dome-shaped height increases with increasing temperature. On the other hand, the simulated model in Abaqus software has a fairly good fit with the experimental model. The best model for predicting precisely the necking momentum was the M-K model.