Mechanical response of zirconium - II. Experimental and finite element analysis of bent beams

In a companion paper [Acta mater. 2001, 49(15), 3085-3096] we develop a pol ycrystal constitutive law that incorporates the deformation mechanisms oper ating in high purity zirconium (Zr) at liquid nitrogen (LN) and room temper ature (RT). In this paper we present results of 4-point bending tests perfo rmed on beams of highly textured zirconium. These tests have been performed at LN and RT, in two orthogonal bending planes, and up to a strain of appr oximately 20% in the outermost fibers of the beams. A novel experimental te chnique, dot-matrix deposition and mapping (DMDM), has been developed and e mployed to analyze the distribution of local plastic strain and macroscopic deformation in the deformed beams, Automated electron backscatter diffract ion (EBSD) pattern analysis has been used to evaluate the textures just bel ow the outermost tensile and compressive surfaces and at the neutral plane. Experimental results compare very well with the predictions of finite elem ent (FE) simulations obtained using the constitutive law developed in Part I. Specifically, we compare local deformation, macroscopic deformation and local texture in the beam. We show that the contribution of twinning to def ormation results in different qualitative responses in the compressive and tensile fibers of the bent beam. Our results indicate the necessity of usin g a constitutive description that accounts for the anisotropy of the aggreg ate and for its evolution with deformation. Published by Elsevier Science L td on behalf of Acta Materialia Inc.