Study on the Formability & Shape Confirmity of Mg & Al-alloy sheets in Warm condition by Electromagnetic Forming

Abstract

Electromagnetic forming is a high strain rate process used for shaping metals. Mg-alloys are of interest by virtue of the light weight and potential for application in automotive industries. These alloys have poor formability at room temperature and have to be formed under warm working conditions. Simulations using COMSOL Multiphysics software were carried out to predict the forming behavior of Mg-alloy sheets deformed at high speeds and different temperatures into a die with a corrugated shape. Conformance of the sheet to the die shape is the objective of this study. These sheets are assumed to be externally heated to different temperatures prior to forming. Possible changes in the mechanical and electrical properties of the material with temperature have been incorporated to show their individual and combined effects. A virtual circuit was built to excite the coil, fully coupled with the Solid Mechanics & Magnetic Fields, through related physics in the software. Optimal parameters that ensure good conformance to die shape are sought as the outcome of the simulation of warm electromagnetic forming of magnesium & aluminium alloy sheets. The quality of strain distribution under different clamping constraints was assessed using the strain non-uniformity index (SNI).