Monitoring microstructural evolution in-situ during cyclic deformation by high resolution reciprocal space mapping

Annika M Diederichs,Torben Fischer,Ulrich Lienert,Wolfgang Pantleon,Felix Thiel

doi:10.1088/1742-6596/843/1/012031

Abstract

The recently developed synchrotron technique High Resolution Reciprocal Space Mapping (HRRSM) is used to characterize the deformation structures evolving during cyclic deformation of commercially pure, polycrystalline aluminium AA1050. Insight into the structural reorganization within single grains is gained by in-situ monitoring of the microstructural evolution during cyclic deformation. By HRRSM, a large number of individual subgrains can be resolved within individual grains in the bulk of polycrystalline specimens and their fate, their individual orientation and elastic stresses, tracked during different loading regimes as tension and compression. With this technique, the evolution of dislocation structures in selected grains was followed during an individual load cycle.

Highlights

Fatigue-related damage due to repeatedly changing mechanical loading is one of the major failure reasons in structural materials
The recently developed synchrotron technique High Resolution Reciprocal Space Mapping (HRRSM) is used to characterize the deformation structures evolving during cyclic deformation of commercially pure, polycrystalline aluminium AA1050
For obtaining reciprocal space maps, the deformation was paused at selected forces: Since the pre-deformation was stopped at the highest compressive load in the hysteresis curve, it was aimed for characterizing the deformation structure after loading the sample with a load as small as permissible to hold the specimen tight

Summary

Introduction

Fatigue-related damage due to repeatedly changing mechanical loading is one of the major failure reasons in structural materials. During cyclic deformation of face-centered cubic metals with high stacking fault energy such as aluminium, dislocations self-organize into ordered structures, consisting of dislocation walls of high dislocation density separating almost dislocation-free subgrains with dimensions of 2-5 μm [2,3,4,5,6,7]. Their specific morphology is influenced by the deformation conditions such as the strain (or stress) amplitude, the strain rate and the number of cycles during cyclic deformation, where higher strain amplitudes causes

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