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Search Publications by: Matthew Connolly (Fed)

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Displaying 26 - 50 of 52

Characteristics and Mechanisms of Hydrogen-Induced Quasi-Cleavage Fracture of Lath Martensitic Steel

January 10, 2021
Author(s)
Lawrence Cho, Peter E. Bradley, Damian S. Lauria, May L. Martin, Matthew J. Connolly, Jake Benzing, Eun Jung Seo, Kip O. Findley, John G. Speer, Andrew J. Slifka
This study presents an in-depth characterization of the microstructures, crystallographic orientations, and dislocation characteristics beneath the hydrogen-induced quasi-cleavage features of an as-quenched, lath martensitic (') 22MnB5 steel. The fracture

Hydrogen embrittlement in ferritic steels

October 6, 2020
Author(s)
May L. Martin, Matthew J. Connolly, Frank W. DelRio, Andrew J. Slifka
The deleterious effects of hydrogen on the physical properties of metals have been known for over a century. Despite extensive work over that time period, there are still significant questions related to the “hydrogen embrittlement” of ferritic steels due

Quasi-elastic Neutron Scattering Measurement of Hydrogen Diffusion in a Graphene Oxide Framework

April 16, 2020
Author(s)
Matthew J. Connolly, Z. N. Buck, Carlos Wexler, Joseph C. Schaeperkoetter, H. Taub, Andrew Gillespie, Helmut Kaiser
We present quasielastic neutron scattering (QENS) spectra from molecular hydrogen adsorbed in GOF. The measurements probed the motion of adsorbed hydrogen as a function of pressure, in order to understand the relationship between the motion of adsorbed

HEXRD Measurement of Strain and Dislocation Density ahead of Crack Tips Grown in Hydrogen

September 13, 2019
Author(s)
Matthew J. Connolly, May L. Martin, Peter E. Bradley, Damian S. Lauria, Andrew J. Slifka, Jun Sang Park, Robert Amaro
The deformation fields near fatigue crack tips grown in hydrogen and in air were measured using high-energy x-ray diffraction. A larger magnitude of elastic strain was observed in the hydrogen case compared to the air case. The magnitude of elastic strain

Fatigue Testing of Pipeline Welds and Heat-Affected Zones in Pressurized Hydrogen Gas

April 26, 2019
Author(s)
Elizabeth S. Drexler, Andrew J. Slifka, Robert L. Amaro, Jeffrey W. Sowards, Matthew J. Connolly, May L. Martin, Damian S. Lauria
Several welds and associated heat-affected zones (HAZs) on two API X70 and two API X52 pipes were tested to determine the fatigue crack growth rate (FCGR) in pressurized hydrogen gas and assess the area of the pipe that was most susceptible to fatigue when

Hydrogen Isotope Effect in Embrittlement and Fatigue Crack Growth of Steel

March 7, 2019
Author(s)
Matthew J. Connolly, Andrew J. Slifka, Robert L. Amaro, Elizabeth S. Drexler, May L. Martin
The corrosive effect of hydrogen on steel is a long-standing problem. Corrosion in the presence of hydrogen is, in part, a consequence of the fast diffusion of hydrogen in ferritic steels. Because of the identical chemical properties but large differences

Demonstration of a Chamber for Strain Mapping of Steel Specimens Under Mechanical Load in a Hydrogen Environment by Synchrotron Radiation

June 4, 2018
Author(s)
Matthew J. Connolly, Peter E. Bradley, Damian S. Lauria, Andrew J. Slifka, Elizabeth S. Drexler
We present a demonstration of a chamber for diffraction measurements of lattice strain for specimens in hydrogen gas under mechanical load. The chamber is suitable for static and cyclic mechanical loading. Synchrotron x-ray radiographs of a fatigue crack

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

April 18, 2018
Author(s)
Matthew J. Connolly, Peter E. Bradley, Damian S. Lauria, Andrew J. Slifka, Elizabeth S. Drexler
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

Chamber for Mechanical Testing in H2 with Observation by Neutron Scattering

June 1, 2017
Author(s)
Matthew J. Connolly, Peter E. Bradley, Andrew J. Slifka, Elizabeth S. Drexler
A gas-pressure chamber has been designed, constructed, and tested at a moderate pressure (3.4 MPa, 500 psi) and has the capability of mechanical loading of steel specimens for neutron scattering measurements. The chamber will allow a variety of in situ

Low-Cycle Fatigue Behavior of Fiber-Laser Welded, Corrosion-Resistant, High-Strength Low Alloy Sheet Steel

February 21, 2017
Author(s)
Jeffrey W. Sowards, Erik A. Pfeif, Matthew J. Connolly, Joseph D. McColskey, Stephanie L. Miller, Brian J. Simonds, James R. Fekete
Incorporation of high-strength steels into ground vehicles provides a weight-savings advantage by using thinner sections of material, which increases vehicle efficiency. Advanced welding techniques such as fiber laser welding are a potential method for