ORCID Profile
0000-0003-4255-1022
Current Organisation
University of Oxford
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.
Publisher: Springer Science and Business Media LLC
Date: 25-10-2019
DOI: 10.1007/S11661-019-05472-X
Abstract: The kinetics of primary α -Ti colony/Widmanstätten plate growth from the β are examined in Ti-6246, comparing a simple quasi-analytic model to experiment. The plate growth velocity depends sensitively both on the diffusivity D ( T ) of the rate-limiting species and on the supersaturation around the growing plate. These result in a maxima in growth velocity around 40 K below the transus, once sufficient supersaturation is available to drive the plate growth. In Ti-6246, the plate growth velocity was found to be around 0.32 μ m min −1 at 850 °C, which was in good agreement with the model prediction of 0.36 μ m min −1 . The solute field around the growing plates, and the plate thickness, was found to be quite variable, due to the intergrowth of plates and soft impingement. This solute field was found to extend to up to 30 nm, and the interface concentration in the β was found to be around 6.4 at. pct Mo. It was found that the increasing O content from 500 to 1500 wppm will have minimal effect on the plate lengths expected during continuous cooling in contrast, Mo approximately doubles the plate lengths obtained for every 2 wt pct Mo reduction. Alloys using V as the β stabilizer instead of Mo are expected to have much faster plate growth kinetics at nominally equivalent V contents. These findings will provide a useful tool for the integrated design of alloys and process routes to achieve tailored microstructures.
Publisher: Elsevier BV
Date: 08-2020
Publisher: Elsevier BV
Date: 05-2018
Publisher: Elsevier BV
Date: 10-2020
Publisher: Elsevier BV
Date: 07-2019
DOI: 10.1016/J.ULTRAMIC.2019.04.005
Abstract: A method for the rapid preparation of atom probe tomography (APT) needles using a xenon plasma-focussed ion beam (FIB) instrument is presented and demonstrated on a test s le of Ti-6Al-4V alloy. The method requires significantly less operator input than the standard lift-out protocol, is site-specific and produces needles with minimal ion-beam damage electron microscopy indicated the needle's surface amorphised/oxidised region to be less than 2 nm thick. The resulting needles were routinely analysable by APT, confirming the expected microstructure and showing negligible Xe contamination.
Publisher: Elsevier BV
Date: 06-2020
Publisher: Oxford University Press (OUP)
Date: 08-2019
Publisher: Springer Science and Business Media LLC
Date: 18-01-2019
DOI: 10.1007/S11661-018-5098-X
Abstract: The formation and evolution of nanoscale γ ″ (Ni 3 (Nb, Ti, Al)) precipitates formed during thermal aging in the nickel superalloy Inconel 625 has been characterized using Atom Probe Tomography. The onset of γ ″ precipitation has been found to occur after only one hour, markedly shorter than the aging time reported in the current literature. Evolution of precipitate composition and morphology during aging has been analyzed, and the potential onset of the γ ″ → δ (Ni 3 (Nb, Mo, Cr, Fe, Ti)) transformation after long aging times is discussed.
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Hazel Gardner.