High heat flux laser testing of HfB2 cylinders
File(s)
Accepted version
Accepted version
Author(s)
Type
Journal Article
Abstract
Hafnium diboride (HfB2) is one of a family of ultra-high temperature
ceramics (UHTCs) which are being considered for
application in environments with a substantial heat flux such as
hypersonic flight. In order to characterize transitions in the
material response with heat flux and therefore predict the inservice
behavior of UHTCs, a range of tests were conducted in
which small cylindrical bars of HfB2 were laser heated using
heat fluxes from 25 to 100 MW/m2. After testing, the external
damage as well as damage observable in cross sections through
the cylinders was characterized using photography, optical, and
scanning electron microscopy. Experimental results were compared
with finite element modeling of the heat flow, temperature
distribution, and phase transition. Heat flux rather than
total deposited heat was found to be the strongest determinant
of the way in which damage develops in samples; for lower heat
fluxes, the main damage mechanism is oxidation, progressing
to oxidation-induced melting and finally, at the highest heat
fluxes, substantial ablation by melting irrespective of oxidation.
The agreement between calculations and experimental observations
indicates that such calculations can be used with confidence
to guide the design of components.
ceramics (UHTCs) which are being considered for
application in environments with a substantial heat flux such as
hypersonic flight. In order to characterize transitions in the
material response with heat flux and therefore predict the inservice
behavior of UHTCs, a range of tests were conducted in
which small cylindrical bars of HfB2 were laser heated using
heat fluxes from 25 to 100 MW/m2. After testing, the external
damage as well as damage observable in cross sections through
the cylinders was characterized using photography, optical, and
scanning electron microscopy. Experimental results were compared
with finite element modeling of the heat flow, temperature
distribution, and phase transition. Heat flux rather than
total deposited heat was found to be the strongest determinant
of the way in which damage develops in samples; for lower heat
fluxes, the main damage mechanism is oxidation, progressing
to oxidation-induced melting and finally, at the highest heat
fluxes, substantial ablation by melting irrespective of oxidation.
The agreement between calculations and experimental observations
indicates that such calculations can be used with confidence
to guide the design of components.
Date Issued
2017-01-01
Date Acceptance
2016-08-03
Citation
Journal of the American Ceramic Society, 2017, 100 (1), pp.293-303
ISSN
1551-2916
Publisher
Wiley
Start Page
293
End Page
303
Journal / Book Title
Journal of the American Ceramic Society
Volume
100
Issue
1
Copyright Statement
This is the peer reviewed version of the following article: Larrimbe, L., Pettinà, M., Nikbin, K., Jones, E. L., Katz, A. P., Hawkins, C. J., DeCerbo, J., Brown, P. and Vandeperre, L. J. (2016), High Heat Flux Laser Testing of HfB2 Cylinders. J. Am. Ceram. Soc., which has been published in final form at https://dx.doi.org/10.1111/jace.14474. This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving.
Sponsor
Defence Science and Technology Laboratory (DSTL)
Defence Science and Technology Laboratory (DSTL)
Grant Number
DSTLX-1000085783
DSTLX1000064072
Subjects
ultra-high temperature ceramics
hafnium diboride
oxidation
melting
laser testing
Publication Status
Published
Date Publish Online
2016-09-12