The effect of different step-size on the visualization of crystallographic defects using SEM/EBSD technique

Ken Shimojima,Yoshikazu Higa,Takashi Makishi

doi:10.1260/1750-9548.9.1.37

Abstract

Crystallographic grains and defects play an important role in many fundamental processes, such as grain growth and recrystallization, damage, and plastic deformation. Due to the importance of these processes, there is considerable interest in characterizing the crystallographic orientation and grain boundary distribution of crystalline materials. In this study, crystallographic defects such as dislocation arrays and grain boundaries and their orientations were investigated in a commercial polycrystalline copper sample using electron backscatter diffraction (EBSD) mapping combined with scanning electron microscopy (SEM). EBSD was used to determine the local orientations at individual points of a regular grid on a planar surface of a specimen. From the orientation differences between neighboring points, the lattice curvature and dislocation density tensor were derived, and the dislocation density distribution accompanying the crystallographic defects was significantly dependent on the SEM/EBSD step size ass...

Highlights

There have been many experimental observations and interesting reports in computational material science based on recent technological developments in micro- to nano-scale observations
Electron beam tomography has been used for in-situ three-dimensional observation of lattice defects in crystallographic metals associated with the elementary processes of plastic deformation [1, 2]
EXPERIMENTAL RESULTS 4.1 CRYSTALLOGRAPHIC ORIENTATION OF THE SPECIMEN The orientations were determined by scanning electron microscopy (SEM)/electron backscatter diffraction (EBSD) at points on a regular “SQUARE GRID”, with a mutual spacing of 1μm

Summary

INTRODUCTION

There have been many experimental observations and interesting reports in computational material science based on recent technological developments in micro- to nano-scale observations. Electron beam tomography has been used for in-situ three-dimensional observation of lattice defects in crystallographic metals associated with the elementary processes of plastic deformation [1, 2]. For the dislocation density tensor associated with the straingradient-dependent crystal plasticity theorem, a technique using white X-ray diffraction for estimating the geometrically necessary dislocation density were developed [3]. Any estimation of the curvature tensor should be strongly dependent on the method used to calculate the spatial gradient and on the number of observation points in its region. This study, involving the visualization of lattice defects in crystalline metals using dislocation density tensor maps, explores the effect of number of observation points on the estimating the curvature and the dislocation density tensor

BASIC RELATION BETWEEN CURVATURE AND DISLOCATION DENSITY TENSOR

OBSERVATION SAMPLE AND ITS CONDITIONS

CONCLUSION