---
_id: '9686'
abstract:
- lang: eng
text: It is well known that ultrasonic vibration can soften metals, and this phenomenon
has been widely exploited in industrial applications concerning metal forming
and bonding. Recent experiments show that the simultaneous application of oscillatory
stresses from audible to ultrasonic frequency ranges can lead to not only softening
but also significant dislocation annihilation and subgrain formation in metal
samples from the nano- to macro-size range. These findings indicate that the existing
understanding of ultrasound softening – that the vibrations either impose additional
stress waves to augment the quasi-static applied load, or cause heating of the
metal, whereas the metal’s intrinsic deformation resistance or mechanism remains
unaltered – is far from complete. To understand the softening and the associated
enhanced subgrain formation and dislocation annihilation, a new simulator based
on the dynamics of dislocation-density functions is employed. This new simulator
considers the flux, production and annihilation, as well as the Taylor and elastic
interactions between dislocation densities. Softening during vibrations as well
as enhanced cell formation is predicted. The simulations reveal the main mechanism
for subcell formation under oscillatory loadings to be the enhanced elimination
of statistically stored dislocations (SSDs) by the oscillatory stress, leaving
behind geometrically necessary dislocations with low Schmid factors which then
form the subgrain walls. The oscillatory stress helps the depletion of the SSDs,
because the chance for them to meet up and annihilate is increased with reversals
of dislocation motions. This is the first simulation effort to successfully predict
the cell formation phenomenon under vibratory loadings.
article_processing_charge: No
article_type: original
author:
- first_name: Bingqing
full_name: Cheng, Bingqing
id: cbe3cda4-d82c-11eb-8dc7-8ff94289fcc9
last_name: Cheng
orcid: 0000-0002-3584-9632
- first_name: H.S.
full_name: Leung, H.S.
last_name: Leung
- first_name: A.H.W.
full_name: Ngan, A.H.W.
last_name: Ngan
citation:
ama: Cheng B, Leung HS, Ngan AHW. Strength of metals under vibrations – dislocation-density-function
dynamics simulations. Philosophical Magazine. 2014;95(16-18):1845-1865.
doi:10.1080/14786435.2014.897008
apa: Cheng, B., Leung, H. S., & Ngan, A. H. W. (2014). Strength of metals under
vibrations – dislocation-density-function dynamics simulations. Philosophical
Magazine. Taylor & Francis. https://doi.org/10.1080/14786435.2014.897008
chicago: Cheng, Bingqing, H.S. Leung, and A.H.W. Ngan. “Strength of Metals under
Vibrations – Dislocation-Density-Function Dynamics Simulations.” Philosophical
Magazine. Taylor & Francis, 2014. https://doi.org/10.1080/14786435.2014.897008.
ieee: B. Cheng, H. S. Leung, and A. H. W. Ngan, “Strength of metals under vibrations
– dislocation-density-function dynamics simulations,” Philosophical Magazine,
vol. 95, no. 16–18. Taylor & Francis, pp. 1845–1865, 2014.
ista: Cheng B, Leung HS, Ngan AHW. 2014. Strength of metals under vibrations – dislocation-density-function
dynamics simulations. Philosophical Magazine. 95(16–18), 1845–1865.
mla: Cheng, Bingqing, et al. “Strength of Metals under Vibrations – Dislocation-Density-Function
Dynamics Simulations.” Philosophical Magazine, vol. 95, no. 16–18, Taylor
& Francis, 2014, pp. 1845–65, doi:10.1080/14786435.2014.897008.
short: B. Cheng, H.S. Leung, A.H.W. Ngan, Philosophical Magazine 95 (2014) 1845–1865.
date_created: 2021-07-19T09:27:15Z
date_published: 2014-06-23T00:00:00Z
date_updated: 2023-02-23T14:04:59Z
day: '23'
doi: 10.1080/14786435.2014.897008
extern: '1'
intvolume: ' 95'
issue: 16-18
language:
- iso: eng
month: '06'
oa_version: None
page: 1845-1865
publication: Philosophical Magazine
publication_identifier:
eissn:
- 1478-6443
issn:
- 1478-6435
publication_status: published
publisher: Taylor & Francis
quality_controlled: '1'
scopus_import: '1'
status: public
title: Strength of metals under vibrations – dislocation-density-function dynamics
simulations
type: journal_article
user_id: 6785fbc1-c503-11eb-8a32-93094b40e1cf
volume: 95
year: '2014'
...
---
_id: '7080'
abstract:
- lang: eng
text: We show evidence that a structural martensitic transition is related to significant
changes in the electronic structure, as revealed in thermodynamic measurements
made in high magnetic fields. The effect of the magnetic field is considered unusual
as many influential investigations of martensitic transitions have emphasized
that the structural transitions are primarily lattice dynamical and are driven
by the entropy due to the phonons. We provide a theoretical framework, which can
be used to describe the effect of the magnetic field on the lattice dynamics in
which the field dependence originates from the dielectric constant.
article_processing_charge: No
article_type: original
author:
- first_name: X.-D.
full_name: Yang, X.-D.
last_name: Yang
- first_name: P.S.
full_name: Riseborough, P.S.
last_name: Riseborough
- first_name: Kimberly A
full_name: Modic, Kimberly A
id: 13C26AC0-EB69-11E9-87C6-5F3BE6697425
last_name: Modic
orcid: 0000-0001-9760-3147
- first_name: R.A.
full_name: Fisher, R.A.
last_name: Fisher
- first_name: C.P.
full_name: Opeil, C.P.
last_name: Opeil
- first_name: T.R.
full_name: Finlayson, T.R.
last_name: Finlayson
- first_name: J.C.
full_name: Cooley, J.C.
last_name: Cooley
- first_name: J.L.
full_name: Smith, J.L.
last_name: Smith
- first_name: P.A.
full_name: Goddard, P.A.
last_name: Goddard
- first_name: A.V.
full_name: Silhanek, A.V.
last_name: Silhanek
- first_name: J.C.
full_name: Lashley, J.C.
last_name: Lashley
citation:
ama: Yang X-D, Riseborough PS, Modic KA, et al. Influence of magnetic fields on
structural martensitic transitions. Philosophical Magazine. 2009;89(22-24):2083-2091.
doi:10.1080/14786430902865518
apa: Yang, X.-D., Riseborough, P. S., Modic, K. A., Fisher, R. A., Opeil, C. P.,
Finlayson, T. R., … Lashley, J. C. (2009). Influence of magnetic fields on structural
martensitic transitions. Philosophical Magazine. Taylor & Francis.
https://doi.org/10.1080/14786430902865518
chicago: Yang, X.-D., P.S. Riseborough, Kimberly A Modic, R.A. Fisher, C.P. Opeil,
T.R. Finlayson, J.C. Cooley, et al. “Influence of Magnetic Fields on Structural
Martensitic Transitions.” Philosophical Magazine. Taylor & Francis,
2009. https://doi.org/10.1080/14786430902865518.
ieee: X.-D. Yang et al., “Influence of magnetic fields on structural martensitic
transitions,” Philosophical Magazine, vol. 89, no. 22–24. Taylor &
Francis, pp. 2083–2091, 2009.
ista: Yang X-D, Riseborough PS, Modic KA, Fisher RA, Opeil CP, Finlayson TR, Cooley
JC, Smith JL, Goddard PA, Silhanek AV, Lashley JC. 2009. Influence of magnetic
fields on structural martensitic transitions. Philosophical Magazine. 89(22–24),
2083–2091.
mla: Yang, X. D., et al. “Influence of Magnetic Fields on Structural Martensitic
Transitions.” Philosophical Magazine, vol. 89, no. 22–24, Taylor &
Francis, 2009, pp. 2083–91, doi:10.1080/14786430902865518.
short: X.-D. Yang, P.S. Riseborough, K.A. Modic, R.A. Fisher, C.P. Opeil, T.R. Finlayson,
J.C. Cooley, J.L. Smith, P.A. Goddard, A.V. Silhanek, J.C. Lashley, Philosophical
Magazine 89 (2009) 2083–2091.
date_created: 2019-11-19T13:48:32Z
date_published: 2009-08-21T00:00:00Z
date_updated: 2023-02-21T16:26:53Z
day: '21'
doi: 10.1080/14786430902865518
extern: '1'
intvolume: ' 89'
issue: 22-24
language:
- iso: eng
month: '08'
oa_version: None
page: 2083-2091
publication: Philosophical Magazine
publication_identifier:
eissn:
- 1478-6443
issn:
- 1478-6435
publication_status: published
publisher: Taylor & Francis
quality_controlled: '1'
related_material:
record:
- id: '11752'
relation: earlier_version
status: public
status: public
title: Influence of magnetic fields on structural martensitic transitions
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 89
year: '2009'
...