Recrystallization texture in nickel heavily deformed by accumulative roll bonding

O V Mishin,A Godfrey,Y B Zhang

doi:10.1088/1757-899x/219/1/012034

Abstract

The recrystallization behavior of Ni processed by accumulative roll bonding to a total accumulated von Mises strain of 4.8 has been examined, and analyzed with respect to heterogeneity in the deformation microstructure. The regions near the bonding interface are found to be more refined and contain particle deformation zones around fragments of the steel wire brush used to prepare the surface for bonding. Sample-scale gradients are also observed, manifested as differences between the subsurface, intermediate and central layers, where the distributions of texture components are different. These heterogeneities affect the progress of recrystallization. While the subsurface and near-interface regions typically contain lower frequencies of cube-oriented grains than anywhere else in the sample, a strong cube texture forms in the sample during recrystallization, attributed to both a high nucleation rate and fast growth rate of cube-oriented grains. The observations highlight the sensitivity of recrystallization to heterogeneity in the deformation microstructure and demonstrate the importance of characterizing this heterogeneity over several length scales.

Highlights

Accumulative roll bonding (ARB) [1,2] is a severe plastic deformation technique, in which a single cycle consists typically of 50% rolling, cutting of the rolled material in half, cleaning and wire brushing of the surface, and stacking the halves prior to repeating this process in subsequent cycles
The recrystallization behavior of Ni processed by accumulative roll bonding to a total accumulated von Mises strain of 4.8 has been examined, and analyzed with respect to heterogeneity in the deformation microstructure
Summary The recrystallization behavior of Ni processed by accumulative roll bonding to a total accumulated von Mises strain of 4.8 has been examined, and analyzed with respect to heterogeneity in the deformation microstructure

Summary

Introduction

Accumulative roll bonding (ARB) [1,2] is a severe plastic deformation technique, in which a single cycle consists typically of 50% rolling, cutting of the rolled material in half, cleaning and wire brushing of the surface, and stacking the halves prior to repeating this process in subsequent cycles This ARB process produces intrinsically heterogeneous microstructures as bonding interfaces are introduced during the multi-pass process. Formation of the cube texture is analyzed in nickel processed by ARB to a high von Mises strain, εvM = 4.8 Both the nucleation and growth of grains with different crystallographic orientations are characterized in this material, and the results are discussed in relation to the microstructural heterogeneities. The results are compared to those obtained for nickel recrystallized after conventional rolling to similar strains

Results

Discussion

Conclusion