Influence of the material microstructural properties on a 3-point bending test

Abstract

The purpose of this study is to highlight the role played by some important factors on sprinback phenomenon. This latter affects significantly the geometry of the manufactured product. Large automotive or plane body parts are specifically affected by this phenomenon which complicates the tools design. The study focuses here on specific materials with high trend to develop heterogeneous strains during forming processes. Due to its hexagonal crystalline structure, titanium has initial heterogeneous microstructure that grows stronger when plastic strain occurs. Heterogeneous microstructures induce the coexistence in the material of volumes with different mechanical properties even, in some case, with different mechanical behaviours. Therefore, accommodation between these volumes generates distributed internal stresses and important elastic energy storage. The macroscopic behaviour can be provided either by average phenomenological constitutive equation identical for all locations in the material or by integrating a set of local constitutive relations taking into account the variability of the behaviour as a function of the position in the material. In this context, experimental and numerical studies of a 3-point bending test on titanium alloy are considered.