In Situ Neutron Transmission Bragg Edge and Synchrotron X-Ray Measurement of Strain Fields Near Fatigue Cracks Grown in Hydrogen

Published: April 18, 2018

Author(s)

Matthew J. Connolly, Peter E. Bradley, Damian S. Lauria, Andrew J. Slifka, Elizabeth S. Drexler

Abstract

The embrittlement and enhanced fatigue crack growth rate of metals in the presence of hydrogen is a long-standing problem. In an effort to determine the dominate damage mechanism behind hydrogen assisted fatigue crack growth, we performed High-Energy X-ray Diffraction (HEXRD) and neutron Transmission Bragg Edge (TBE) measurements to characterize the strain fields near cracks grown both in air as well as in a hydrogen environment. An enhancement in the magnitude and spatial extent of the strain field near the crack grown in hydrogen compared to near the crack grown in air was observed. We discuss the differences between the measured in-air and in- hydrogen crack-tip strain fields in the context of the two leading damage mechanisms proposed in the literature.
Proceedings Title: Proceedings of the 9th International Conference on Mechanical Stress Evaluation by Neutron and Synchrotron Radiation, MECA SENS 2017
Volume: 4
Conference Dates: September 18-22, 2017
Conference Location: Skukuza, -1
Conference Title: 9th International Conference on Mechanical Stress Evaluation by Neutron and Synchrotron Radiation, MECA SENS 2017
Pub Type: Conferences

Keywords

Neutron, Bragg Edge, Strain, Hydrogen, Fracture, Fatigue, Synchrotron, Diffraction
Created April 18, 2018, Updated November 10, 2018