AZ31 Magnesium Alloy Parameters Identification through Inverse Analysis at 713 K

Abstract

This paper introduces a fast and accurate procedure for determining the constants of magnesium AZ31 alloy at 713 K. The material behaviour is modelled by means of the power law relationship between the equivalent flow stress, the equivalent strain and the equivalent strain-rate within a narrow equivalent strain-rate range. Bulging tests were carried out in isothermal conditions (713 K) and at constant pressure in order to determine the material constants. It is necessary to evaluate the displacement and the thickness evolutions at the dome apex of the metal sheet. The time-displacement curve was obtained by laser measurements whereas a large number of bulging tests, interrupted at preset time intervals, were carried out to evaluate the thickness. The thickness was measured directly using a two-digit micrometer. The material constants, m, n and K were obtained in the power law relationship by means of constant pressure bulging tests coupled with the use of an inverse analysis technique. The results of comparison between experimental and numerical tests are shown and they indicate that the material constants can be accurately evaluated.