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Search Publications by May Martin

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Displaying 1 - 14 of 14

Experimental study of shear and tensile properties of LIGA Ni-Fe and Ni-Co alloys at quasi-static and intermediate strain rates

April 1, 2021
Li-Anne Liew, David T. Read, May Martin, Todd R. Christenson, Peter E. Bradley, Nicholas Barbosa, Frank W. DelRio, John T. Geaney, Jeffrey Smyth
We report the in-plane shear properties, to fracture, of 200 um-thick LIGA nanocrystalline Ni- 10%Fe and micrograined Ni-10%Co. Planar simple shear specimens were designed, fabricated and pulled to fracture using a miniature commercial tension test stage

Influence of H2S on the pitting corrosion of 316L stainless steel

January 18, 2021
James Hesketh, E.J.F. Dickinson, May Martin, G. Hinds, Alan Turnbull
Coupon immersion tests were performed on 316L stainless steel in a simulated oilfield environment to evaluate the effect of H2S partial pressure on pit depth and density. Pitting was most significant at intermediate partial pressures of H2S, for which free

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

January 10, 2021
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

Elastic-plastic properties of mesoscale electrodeposited LIGA nickel alloy films: microscopy and mechanics

November 22, 2020
Li-Anne Liew, David T. Read, May Martin, Frank W. DelRio, Peter E. Bradley, Nicholas Barbosa, Todd R. Christenson, John T. Geaney
The elastic-plastic properties of mesoscale electrodeposited LIGA Ni alloy specimens are investigated as a function of specimen size, strain rate, and material composition. Two material compositions are studied: a high-strength fine-grained Ni-Fe alloy and

Hydrogen embrittlement in ferritic steels

October 6, 2020
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

Dominant factors for fracture at the micro-scale in electrodeposited nickel alloys

August 1, 2020
May L. Martin, Li-Anne Liew, David T. Read, Todd Christensen, Frank W. DelRio, John Geaney
Two different LIGA electrodeposited nickel alloys displayed distinct fracture modes after meso- scale tensile testing. The Ni-Co alloy failed in a ductile manner, while the Ni-Fe alloy failed in a more brittle-appearing manner. Various factors affecting

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

September 13, 2019
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
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
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