Texture formation in orthorhombic alpha-uranium under simple compression and rolling to high strains

Abstract

h i g h l i g h t sA multi-scale finite element model is built to simulate behavior of a-U to large plastic strains. Development of texture gradients during rolling in a-U is captured by the model. Role of deformation mechanisms in texture formation of a-U is discussed.Twinning is profuse during rolling but not active during through-thickness compression. Floor slip is responsible for the formation of two pronounced {001} texture peaks in rolling. a b s t r a c tWe study the mechanical response and texture evolution of alpha-uranium during simple compression and rolling at 573 K. In order to determine the underlying mechanisms governing plasticity and texture formation, we perform detailed characterizations using electron backscattered diffraction and constitutive modeling using a dislocation-density based hardening law within a visco-plastic self-consistent homogenization. We show that the model achieves good agreement with experimental measurements in terms of texture and stressestrain response. From detailed comparison of experimental and modeling results, we infer that in both through-thickness compression (TTC) and rolling at 573K, the active slip modes are floor slip (001)[100] and chimney slip 1=2f110g〈110〉 with slightly different ratios. However, f130g〈310〉 twinning is not active in TTC compression but profuse during rolling. Further analysis indicates that during rolling, floor slip (001)[100] results in the formation of two pronounced (001) texture peaks tilted 10e15 away from the normal toward the rolling direction.

Multiscale Modeling of Microstructure‐Property Relationships of Polycrystalline Metals during Thermo‐Mechanical Deformation

“…The model was developed and with a single set of material parameters produces compression stress–strain curves for α ‐U in agreement with experimental measurement at a wide range of temperatures (273–573 K) and in three orthogonal directions (see Figure ). The parameters are reported in ref . In what follows, we describe its use in a multiscale model that aims to examine heterogeneous texture development through the thickness of the sample during rolling.…”

“…Comparison of measured (solid lines) versus simulated (dashed lines) true stress–true strain response in compression of clock rolled α ‐U in three different directions (in‐plane direction 1, in‐plane direction 2, and through‐thickness 3) as a function of temperature …”

“…The initial 2D mesh of 1/2 of the sheet consisting of 396 CPE4 plane strain elements. b) Fields of equivalent plastic strain (PEEQ) as predicted by the FE‐VPSC model Reproduced with permission, 2017, Elsevier.…”

“…Pole figures showing the comparison between measured and predicted texture evolution at a polycrystalline material point near the bottom surface of the sheet Reproduced with permission, 2017, Elsevier. The IP1 direction is the transverse direction and IP2 is the rolling direction.…”

The plasticity of highly oriented nano-layered Zr/Nb composites

“…The overall model is referred to be the DD-CPFE model. The model assumes that dislocations are stored according to thermally activated rate laws and as a consequence, the resistance stresses τ c s are a function of strain, temperature, and strain rate [30,[42][43][44][45][46][47][48][49][50]. This law is applied to every slip system s in Zr and Nb.…”