Experimental Investigation of the Formability Improvement of Brass ۲۶۰ and Al۵۱۸۲-O in Various Strain Rate using Hydrodynamic and Electrohydraulic Forming Methods

Studying the formability of the sheet metals have been the subject of many researches during the last decades. A number of experimental and numerical approaches were implemented to derive the formability diagrams of different materials. In this study, the formability of two mostly used alloys, Brass ۲۶۰ and Al۵۱۸۲-O as low and moderate formability materials, were investigated respectively. The forming limit diagrams of both materials were determined by using three experimental approaches such as Nakazima quasi-static as low strain rate method, hydrodynamic forming method as the moderate strain rate method and Electrohydraulic Forming process as high strain rate method. Three experimental results of forming limit diagram with the various strain rate were compared graphically. The results have shown that both of the materials could withstand higher strains when the electrohydraulic forming method was applied on the specimens and consequently, the forming limit diagrams for Brass ۲۶۰ and Al۵۱۸۲-O shift up by ۱۱% and ۱۴%, respectively. In addition, it was concluded that the hydrodynamic forming method improves the formability of the materials by ۴% and ۶% for Brass ۲۶۰ and Al۵۱۸۲-O, respectively. The outcomes of this study indicated that the formability of both materials was improved significantly by increasing the strain rate.

Keywords:

Electrohydraulic Forming Process (EHF) , Forming Limit Diagrams (FLD) , Formability , Hydrodynamic Forming Method , Nakazima Test