Evidence that abnormal grain growth precedes fatigue crack initiation in nanocrystalline Ni-Fe

SCRIPTA MATERIALIA

卷:143

Article

Furnish, Timothy A.¹  Bufford, Daniel C.¹  Ren, Fang²  Mehta, Apurva²  Hattar, Khalid¹  Boyce, Brad L.¹ 

[1] Sandia Natl Labs, Mat Phys & Chem Sci Ctr, POB 5800, Albuquerque, NM 87185 USA

[2] Stanford Synchrotron Radiat Lightsource, Menlo Pk, CA USA

关键词: Nanocrystalline;    Fatigue;    Fracture;    Nanostructure;    X-ray diffraction;   

DOI  :  10.1016/j.scriptamat.2017.08.047

来源: Elsevier

【 摘 要 】

Prior studies on the high-cycle fatigue behavior of nanocrystalline metals have shown that fatigue fracture is associated with abnormal grain growth (AGG). However, those previous studies have been unable to determine if AGG precedes fatigue crack initiation, or vice-versa. The present study shows that AGG indeed occurs prior to crack formation in nanocrystalline Ni-Fe by using a recently developed synchrotron X-ray diffraction modality that has been adapted for in-situ analysis. The technique allows fatigue tests to be interrupted at the initial signs of the AGG process, and subsequent microscopy reveals the precursor damage state preceding crack initiation. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd.

【 授权许可】

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