Following Microstructures during Deformation: In situ X-ray/Neutron Diffraction and HRDIC

E Polatidis,H Van Swygenhoven,K Sofinowski,W-N Hsu

doi:10.1088/1757-899x/580/1/012010

Abstract

The mechanical behavior of three engineering materials is studied employing in situ deformation methods. The study covers metastable austenitic steels with different stacking fault energies during multiaxial loading, a Ti-6Al-4V alloy processed by electron beam melting during uniaxial deformation and a commercial nanocrystalline NiTi alloy during multiaxial deformation. The experimental results obtained by in situ X-ray or neutron diffraction elucidate the load transfer and phase transformation mechanisms, information that is averaged over a relatively large volume containing a statistically representative number of grains. Complementary in situ high resolution digital image correlation allows details to be revealed regarding the localized strain accommodation and slip activity with a sub-grain spatial resolution. It is demonstrated that the synergy of the different length-scale investigations provides a better understanding of the complex relationship between microstructure and deformation behavior in these materials.

Highlights

In situ neutron and synchrotron x-ray diffraction are well established techniques for studying internal stress and microstructure evolution [1,2,3]
In situ high resolution digital image correlation (HRDIC) can offer a direct link between the microstructure and the strain produced by dislocation slip, twinning and martensitic phase transformations when the evolution during deformation is monitored in the same material portion
Summary Three examples have been presented to highlight the complementary aspects of HRDIC and in situ diffraction methods for investigating the mechanical behavior of engineering materials

Summary

Introduction

In situ neutron and synchrotron x-ray diffraction are well established techniques for studying internal stress and microstructure evolution [1,2,3]. The technique has the advantage of providing average information over relative large volumes that are representative of the studied microstructure. It misses, direct spatial microstructure correlations, i.e. observations in individual grains, grain interactions or strain concentrations in particular places.

Published under licence by IOP Publishing Ltd

Methods

Single slip Multi slip