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Enhanced temperature uniformity by tetrahedral laser heating

Schroers, Jan and Bossuyt, Sven and Rhim, Won-Kyu and Li, Jianzhong and Zhou, Zhenhua and Johnson, William L. (2004) Enhanced temperature uniformity by tetrahedral laser heating. Review of Scientific Instruments, 75 (11). pp. 4523-4527. ISSN 0034-6748. http://resolver.caltech.edu/CaltechAUTHORS:SCHRrsi04

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Abstract

emperature profile on a spherical sample that is heated by laser beams in various geometries while processed in vacuum is analyzed. Sample heating by one or four laser beams was considered. An analytical expression was derived for directional sample heating cases. It suggests an enhanced temperature uniformity over the samples when heated with four diffuse laser beams arranged in a tetrahedral geometry. This was experimentally verified by heating a spherical stainless steel sample by laser beams. Both the calculated and experimentally determined temperature variations over the sample suggest that use of diffuse four beams arranged in tetrahedral geometry would be effective in reducing temperature variation to within 1 K. The enhancement in the temperature uniformity for four diffuse beams arranged in a tetrahedral geometry by a factor of 50 over a single focused beam is promising to accurately measure of thermophysical properties. This drastic improvement in temperature uniformity might even enable atomic diffusion measurements in the undercooled liquid states of the bulk glass forming alloys since Marangoni and gravity driven convection will be substantially reduced.


Item Type:Article
Additional Information:©2004 American Institute of Physics (Received 25 February 2004; accepted 18 August 2004; published online 29 October 2004) This work was supported by the National Aeronautics and Space Administration (Grant No. NAG8-1744). The authors express their gratitude to Sundeep Mukherjee for technical assistance.
Subject Keywords:diffusion; stainless steel; laser materials processing; convection; drops; laser beam effects; thermal conductivity; thermocouples; temperature measurement
Record Number:CaltechAUTHORS:SCHRrsi04
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:SCHRrsi04
Alternative URL:http://dx.doi.org/10.1063/1.1804351
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:4930
Collection:CaltechAUTHORS
Deposited By: Archive Administrator
Deposited On:13 Sep 2006
Last Modified:11 Dec 2014 00:30

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