INHOMOGENEOUS AND ANISOTROPIC DEFORMATION BEHAVIOR AND STRAIN HARDENING OF ULTRAFINE-GRAINED ALUMINIUM BY ECAP

摘要

Hot-rolled AA1050 commercial pure aluminum was deformed by ECAP (Equal Channel Angular Pressing) at room temperature following route B_c for 8 passes. Mechanical testing at room temperature on both hot-rolled aluminum and aluminum after ECAP consisted of uniaxial tension, axisymmetric compression and shear by torsion. The phenomenological Hill's criterion identified from texture data accounts for the observed tension-compression asymmetry due to ECAP and predicts torsion yielding close to measurements. FE simulations of the compression tests are performed with a Hill model or a Minty micro-macro model and coupled with an isotropic Voce saturation hardening law. These simulations compute the inhomogeneous behavior due to barreling, the observed sample anisotropy and the force-displacement curve. Comparisons of numerical and experiments results provide a first identification of the hardening parameters and the friction coefficient during compression tests.