Constitutive Modeling for the Simulation of the Superplastic Forming of AA5083

Abstract

The AA5083 alloy is already being used in applications that require lightweight construction and moderate strengths. In order to carry out accurate simulations of the superplastic forming of this alloy, the used constitutive models should be able to predict the deformation and thinning behavior during the forming process. In this paper, we compare the dome height and pole thickness evolution during gas bulge forming using different AA5083 constitutive material models. The models considered have different levels of complexity and are fitted using either tensile or biaxial experimental data. The simulation results are also compared with experimental data from literature. In addition, recommendations are made for developing accurate material models for the considered AA5083 alloy.

An Accurate Constitutive Model for AZ31B Magnesium Alloy during Superplastic Forming

“…Accurate constitutive material models are essential for the realistic simulation of the SPF process. Many established models found in the literature are identified as phenomenological material models [6][7][8][9][10][16][17][18][19][20][21]. These are viscoplastic models that represent the macroscopic behavior of deformation, usually at a constant forming temperature.…”

“…They reflect mainly the relationship between the effective flow stress and the effective strain and strain rate. The constants in these models are fitted using uniaxial tensile [10] or bulge forming experimental data [9,20,21].…”

“…When incorporated in the simulation of superplastic forming (SPF), the simple material models were reported to produce unsatisfactory results [6][7][8][9][10]. The main reason many studies rely on simple material models is the difficulty in determining the material constants.…”

Characterization of OT4-1 Alloy by Multi-Dome Forming Test

“…Low level of flow stress and high strain rate sensitivity of the material are the main features of superplastic deformation. In order to describe material behavior during superplastic deformation, the Backofen constitutive equation [ 2 ], using power relation between flow stress and strain rate , is commonly used [ 3 , 4 ] where and are the material constants. The strain rate sensitivity index is an important parameter responsible for the stability of plastic flow.…”

“…The coefficients of Equation (1) are calculated by the approximation of the measured flow stress values for different strain rates. However, in some investigations [ 3 , 6 , 7 , 8 , 9 ] it was shown that free bulging testing is a more suitable experimental technique for characterization of a material formed in biaxial tension conditions. The comparison of material characteristics obtained by free bulging and tensile tests for aluminum based alloys is presented in [ 6 , 7 , 8 , 9 ].…”