Deformation compatibility in a single crystalline Ni superalloy.

Jun Jiang,T Ben Britton,Fionn P E Dunne,Tiantian Zhang

doi:10.1098/rspa.2015.0690

Abstract

Deformation in materials is often complex and requires rigorous understanding to predict engineering component lifetime. Experimental understanding of deformation requires utilization of advanced characterization techniques, such as high spatial resolution digital image correlation (HR-DIC) and high angular resolution electron backscatter diffraction (HR-EBSD), combined with clear interpretation of their results to understand how a material has deformed. In this study, we use HR-DIC and HR-EBSD to explore the mechanical behaviour of a single-crystal nickel alloy and to highlight opportunities to understand the complete deformations state in materials. Coupling of HR-DIC and HR-EBSD enables us to precisely focus on the extent which we can access the deformation gradient, F, in its entirety and uncouple contributions from elastic deformation gradients, slip and rigid body rotations. Our results show a clear demonstration of the capabilities of these techniques, found within our experimental toolbox, to underpin fundamental mechanistic studies of deformation in polycrystalline materials and the role of microstructure.

Highlights

Characterizing and understanding the deformation behaviour of crystalline materials at microstructure scale are of great importance to further improve materials’ strength and integrity performance, e.g. fracture and fatigue crack nucleation life [1,2,3]
We focus on understanding deformation in a single crystal of an Ni superalloy at room temperature, which deforms through dislocation mediated plasticity, and enables us to explain relative contributions to the total deformation gradient and elastic deformation gradient terms which can be accessed with high spatial resolution digital image correlation (HR-digital image correlation (DIC)) and high angular resolution electron backscatter diffraction (HR-electron backscatter diffraction (EBSD)), respectively
We demonstrate that the combination of HR-DIC and HR-EBSD techniques provides unique and comprehensive information on understanding deformation processes in crystalline materials

Summary

Introduction

Characterizing and understanding the deformation behaviour of crystalline materials at microstructure scale are of great importance to further improve materials’ strength and integrity performance, e.g. fracture and fatigue crack nucleation life [1,2,3]. These are required to design higher performance components suitable for.

Objectives

Findings

Discussion

Conclusion