Theoretical and experimental evaluation of the formability of anisotropic zinc sheets
Formability of metal sheet has been widely studied for the past 40 years. This study leads to the well known Forming Limit Diagram (FLD) proposed by Keeler and Backhofen . Such a diagram needs typical drawing and stretching experiments to be achieved. Lots of different metals have been considered as steel, aluminium, titanium or magnesium alloys . Despite of the large amount of papers about sheet metal forming, few deal with Zinc sheets. The material has an anisotropic mechanical response due to its hexagonal crystallographic lattice and its microstructural texture. In the presented work, Nakazima and tensile tests have been performed for different mechanical orientations (0°, 45° and 90° angle to the rolling direction) in order to characterise this typical response. A high anisotropic behaviour has been noticed for the hardening and for the critical strains. The FLD is therefore a function of the orientation. Moreover thickness sensitivity is observed and leads to some criticisms about the plane stress assumption usually used in the FLD predictive models [3, 4]. The Modified Maximum Force Criterion (MMFC) is evaluated, and discussed. Then, this model is compared to a damage model used in  within an FEM formulation. © (2011) Trans Tech Publications.
Keywords: Anisotropy ; Critical strains ; Crystallographic lattices ; Crystallography ; Damage ; Damage model ; Drawing (forming) ; Experimental evaluation ; Formability ; Forming limit diagrams ; Magnesium ; Magnesium alloys ; Mechanical orientation ; Mechanical response ; Metal forming ; Metals ; Metal sheets ; Microstructural texture ; Necking ; Paper sheeting ; Plane stress ; Predictive models ; Rolling direction ; Sheet metal ; Single crystals ; Tensile testing ; Tensile tests ; Thickness sensitivity ; Titanium ; Titanium alloys ; Zinc ; Zinc sheets
Record created on 2014-11-14, modified on 2016-08-09