Review of warm forming of aluminum-magnesium alloys

This paper introduces a set of coupled viscoplastic constitutive equations for deformation and damage in hot stamping and cold die quenching of AA6082 panel parts The equation set can be used to predict viscoplastic flow and plasticity-induced damage of AA6082 under hot forming conditions Deformation and damage depend upon a coupled set of evolving internal state variables, eg dislocation density, which in turn is affected by thermally activated and deformation-dependent recrystallisation and recovery A phenomenological description of damage is derived based on the expected physical scaling with temperature, strain and strain rate The resulting equations were implemented in the commercial software ABAQUS via the user-defined subroutine VUMAT for carrying out forming process simulations An experimental programme was designed, and specialised testing facilities developed for calibrating and validating the FE process modelling results A good agreement between the process simulation and the experimental results has been achieved This confirms that the physical dependencies in the constitutive equations are correctly formed, and that the equations and FE model can be calibrated and used for hot stamping of AA6082 panel parts Further, forming process optimisation was carried out using the model to identify the optimal forming parameters for a basic panel part with a circular hole in the middle The study concludes with a discussion of the potential impact of the constitutive model, experimental characterisation and modelling results on AA6082 panel parts manufacture

Investigation of deformation and failure features in hot stamping of AA6082: Experimentation and modelling

Forming of AA5182-O and AA5754-O at elevated temperatures using coupled thermo-mechanical finite element models

A review of planar biaxial tensile test systems for sheet metal

Forming of aluminum alloys at elevated temperatures – Part 1: Material characterization

Uniaxial tensile deformation behavior of three aluminum sheet alloys, Al 5182+1% Mn, Al 5754 and Al 6111-T4, are studied in the warm forming temperature range of 200–350 °C and in the strain rate range of 0.015–1.5 s −1 . Approaches have been made to process the selected aluminum sheet alloys so that the microstructural change during warm forming provides adequate recovery favorable to formability but does not deteriorate the post-forming properties. The total elongation in uniaxial tension is found to increase with increasing temperature and to decrease with increasing strain rate. The enhanced ductility at elevated temperatures is contributed primarily from the post-uniform elongation which becomes dominant at elevated temperatures and/or at slow strain rates. The enhancement of strain rate sensitivity ( m value) with increasing temperature accounts for the ductility improvement at elevated temperatures. The uniaxial tensile test is identified to serve as a screening test for ranking relative formability among different sheet alloys. Based on this criterion, the strain hardened 5xxx alloys (Al 5182+Mn and Al 5754) have shown better formabilities than the precipitation hardened alloy (Al 6111-T4).

Daoming Li

Papers

Tensile deformation behavior of aluminum alloys at warm forming temperatures

Biaxial warm forming behavior of aluminum sheet alloys

Incorporation of Nicandra physalodes (Linn.) Gaertn. pectin as a way to improve the textural properties of fish gelatin gels