ORCID Profile
0000-0002-2607-4388
Current Organisations
University of Oxford
,
University of Sydney
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Materials Engineering | Metals and Alloy Materials | Materials engineering | Nanoscale Characterisation | Metals and alloy materials
Hydrogen Distribution | Hydrogen Storage | Structural Metal Products |
Publisher: The Royal Society
Date: 12-06-2017
Abstract: This discussion session concerned experimental and theoretical investigations of the atomistic properties underlying the energetics and kinetics of hydrogen trapping and diffusion in metallic systems. This article is part of the themed issue ‘The challenges of hydrogen and metals’.
Publisher: Elsevier BV
Date: 09-2022
Publisher: Elsevier BV
Date: 11-2023
Publisher: Wiley
Date: 18-02-2021
Publisher: American Vacuum Society
Date: 27-03-2018
DOI: 10.1116/1.5024852
Abstract: It has been a general trend to develop low-voltage electron microscopes due to their high imaging contrast of s les and low radiation damage. Atomic-lattice-resolved transmission electron microscopes with voltages as low as 15–40 kV have been demonstrated. However, achieving an atomic resolution at voltages lower than 10 kV is extremely difficult. An alternative approach is a coherent imaging or phase retrieval imaging, which requires a sufficiently coherent source, an adequately small illumination area on the s le, the detection of high-angle diffraction patterns with a sufficient signal-to-noise ratio, and an appropriate theoretical reconstruction algorithm. This study proposes several transmission-type schemes to achieve coherent imaging of thin materials (less than 5 nm thick) with atomic resolution at voltages lower than 10 kV. Experimental schemes of both lens-less and lens-containing designs and preliminary results based on a highly coherent single-atom electron source are presented. The image plate is designed to be retractable to record the transmission patterns at different positions along the beam propagation direction. In addition, the authors proposed reflection-type coherent electron imaging schemes as novel methods for characterizing surface atomic and electronic structures of materials. The ultimate goal is to achieve high-contrast and high-spatial-resolution imaging of thin materials, such as two-dimensional materials, or molecules, such as organic or biological molecules, under low-dose conditions.
Publisher: Elsevier BV
Date: 06-2022
Publisher: Elsevier BV
Date: 05-2023
Publisher: American Association for the Advancement of Science (AAAS)
Date: 17-03-2017
Abstract: The design of atomic-scale microstructural traps to limit the diffusion of hydrogen is one key strategy in the development of hydrogen-embrittlement-resistant materials. In the case of bearing steels, an effective trapping mechanism may be the incorporation of finely dispersed V-Mo-Nb carbides in a ferrite matrix. First, we charged a ferritic steel with deuterium by means of electrolytic loading to achieve a high hydrogen concentration. We then immobilized it in the microstructure with a cryogenic transfer protocol before atom probe tomography (APT) analysis. Using APT, we show trapping of hydrogen within the core of these carbides with quantitative composition profiles. Furthermore, with this method the experiment can be feasibly replicated in any APT-equipped laboratory by using a simple cold chain.
Publisher: Oxford University Press (OUP)
Date: 07-2017
Publisher: Springer Science and Business Media LLC
Date: 06-02-2018
DOI: 10.1007/S10853-017-1978-5
Abstract: Hydrogen embrittlement is a complex phenomenon, involving several length- and timescales, that affects a large class of metals. It can significantly reduce the ductility and load-bearing capacity and cause cracking and catastrophic brittle failures at stresses below the yield stress of susceptible materials. Despite a large research effort in attempting to understand the mechanisms of failure and in developing potential mitigating solutions, hydrogen embrittlement mechanisms are still not completely understood. There are controversial opinions in the literature regarding the underlying mechanisms and related experimental evidence supporting each of these theories. The aim of this paper is to provide a detailed review up to the current state of the art on the effect of hydrogen on the degradation of metals, with a particular focus on steels. Here, we describe the effect of hydrogen in steels from the atomistic to the continuum scale by reporting theoretical evidence supported by quantum calculation and modern experimental characterisation methods, macroscopic effects that influence the mechanical properties of steels and established damaging mechanisms for the embrittlement of steels. Furthermore, we give an insight into current approaches and new mitigation strategies used to design new steels resistant to hydrogen embrittlement.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 10-01-2020
Abstract: Hydrogen is important for energy applications such as fuel cells but tends to diffuse into materials and make them more susceptible to fracture. Chen et al. tackled the challenge of identifying the exact location of hydrogen atoms in two common steels. The light weight and high mobility of hydrogen creates serious problems with conventional techniques. The authors used cryo-transfer atom probe tomography to show that hydrogen is pinned to various interfaces in the steels. This direct look into hydrogen trapping should help with the development of materials that are more resistant to hydrogen embrittlement. Science , this issue p. 171
Publisher: Oxford University Press (OUP)
Date: 08-2019
Publisher: American Vacuum Society
Date: 22-12-2016
DOI: 10.1116/1.4938408
Abstract: In this work, a transmission-type, low-kilovolt coherent electron diffractive imaging instrument was constructed. It comprised a single-atom field emitter, a triple-element electrostatic lens, a s le holder, and a retractable delay line detector to record the diffraction patterns at different positions behind the s le. It was designed to image materials thinner than 3 nm. The authors analyzed the asymmetric triple-element electrostatic lens for focusing the electron beams and achieved a focused beam spot of 87 nm on the s le plane at the electron energy of 2 kV. High-angle coherent diffraction patterns of a suspended graphene s le corresponding to (0.62 Å)−1 were recorded. This work demonstrated the potential of coherent diffractive imaging of thin two-dimensional materials, biological molecules, and nano-objects at a voltage between 1 and 10 kV. The ultimate goal of this instrument is to achieve atomic resolution of these materials with high contrast and little radiation damage.
Publisher: Oxford University Press (OUP)
Date: 07-2017
Publisher: Elsevier BV
Date: 12-2019
Publisher: The Royal Society
Date: 12-06-2017
Abstract: The final session of the meeting consisted of a discussion panel to propose future directions for research in the field of hydrogen embrittlement and the potential impact of this research on public policy. This article is part of the themed issue ‘The challenges of hydrogen and metals’.
Publisher: Oxford University Press (OUP)
Date: 08-2019
Publisher: Research Square Platform LLC
Date: 14-02-2022
DOI: 10.21203/RS.3.RS-1325909/V1
Abstract: Hydrogen embrittlement in steel gas infrastructure is a serious challenge for the use of hydrogen energy for global decarbonization. Steel gas pipelines contain a significant fraction of pearlite, which consists of lamellar cementite in ferrite. How exactly hydrogen affects deformation and failure in this structure, and hence the role that pearlite plays in embrittlement, is not well understood. Here we have studied the behavior of hydrogen around the cementite–ferrite interface, the defining microstructural feature in pearlite. Our micromechanical testing results show softening in the ferrite adjacent to the interface, consistent with hydrogen-enhanced local plasticity, rather than interfacial weakening. Atom probe tomography (APT) observations of hydrogen at the interface show no evidence of trapping at the cementite–ferrite interface, instead hydrogen trapping in pearlite occurs in the cementite bulk. Density functional theory calculations, accounting for the configuration of the lattice defects and local interfacial misfits, are consistent with the experimental observations. These findings explain how hydrogen leads to degradation in pearlite. This information is critical for the development of next-generation pipeline materials that can better withstand hydrogen embrittlement.
Publisher: Oxford University Press (OUP)
Date: 08-2015
Publisher: Oxford University Press (OUP)
Date: 20-12-2022
Abstract: Atom probe tomography (APT) is an emerging microscopy technique that has high sensitivity for hydrogen with sub-nanometre-scale spatial resolution, which makes it a unique method to investigate the atomic-scale distribution of hydrogen at interfaces and defects in materials. This article introduces the basics of APT-based hydrogen analysis, particularly the challenge of distinguishing a hydrogen background signal in APT by using hydrogen isotopes, along with strategies to yield high-quality analysis. This article also reviews several important findings on hydrogen distribution in a range of materials, including both structural alloys and functional materials, enabled by using APT. Limitations and future opportunities for hydrogen analysis by APT are also discussed.
Publisher: Wiley
Date: 13-12-2020
Abstract: Hydroxyapatite nanoparticles (HAP NPs) are important for medicine, bioengineering, catalysis, and water treatment. However, current understanding of the nanoscale phenomena that confer HAP NPs their many useful properties is limited by a lack of information about the distribution of the atoms within the particles. Atom probe tomography (APT) has the spatial resolution and chemical sensitivity for HAP NP characterization, but difficulties in preparing the required needle-shaped s les make the design of these experiments challenging. Herein, two techniques are developed to encapsulate HAP NPs and prepare them into APT tips. By sputter-coating gold or the atomic layer deposition of alumina for encapsulation, partially fluoridated HAP NPs are successfully characterized by voltage- or laser-pulsing APT, respectively. Analyses reveal that significant tradeoffs exist between encapsulant methods/materials for HAP characterization and that selection of a more robust approach will require additional technique development. This work serves as an essential starting point for advancing knowledge about the nanoscale spatiochemistry of HAP NPs.
Publisher: Springer Science and Business Media LLC
Date: 05-04-2018
Publisher: Elsevier BV
Date: 04-2021
Location: United Kingdom of Great Britain and Northern Ireland
Start Date: 2019
End Date: 2021
Funder: Australian Research Council
View Funded ActivityStart Date: 2019
End Date: 2019
Funder: Australian Research Council
View Funded ActivityStart Date: 06-2019
End Date: 12-2024
Amount: $321,269.00
Funder: Australian Research Council
View Funded ActivityStart Date: 07-2023
End Date: 07-2023
Amount: $477,237.00
Funder: Australian Research Council
View Funded ActivityStart Date: 06-2023
End Date: 06-2026
Amount: $519,346.00
Funder: Australian Research Council
View Funded Activity