Hoult, A. P. (1999) An experimental analysis of solid state pulsed laser melting of aluminium. PhD thesis, University of Warwick.

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Abstract

Novel aspects of solid state laser spot melting of aluminium using a pulsed solid
state laser were investigated. After a thorough characterisation of the performance of
the solid state laser, an initial series of ranging trials were performed to identify
parameters which produced cosmetically satisfactory consistent melt spots on the
surface of a commercially available aluminium alloy. These melt spots demonstrated a
number of features of interest, including symmetrical concentric ring structures on the
surface of the spots. A review of published literature on the use of laser beams as an
intense radiation source for pulsed laser surface melting was carried out which
confirmed that these phenomena have not been researched or reported in any depth.
Experimental work identified the conditions under which they could be reliably
reproduced, and these conditions are very close to laser parameters used commercially
for pulsed laser welding. Further investigations to understand their origin involved
using modified aluminium surfaces and temporally shaped laser pulses. Experimental
details are included which will allow reliable reproduction of this effect in the future.
Specific thresholds were identified for these phenomena and this has led to an
improved understanding of solid state laser spot melting on aluminium. It appears that
these rings are part of a continuum of irradiance which leads to melt expulsion due to
reactive vapour pressure.

Item Type:	Thesis or Dissertation (PhD)
Subjects:	T Technology > TN Mining engineering. Metallurgy
Library of Congress Subject Headings (LCSH):	Solid-state lasers, Aluminum -- Metallurgy
Official Date:	February 1999
Dates:	Date Event February 1999 Submitted
Institution:	University of Warwick
Theses Department:	School of Engineering
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Pashby, I. R.
Extent:	206, [49] leaves
Language:	eng
URI:	http://wrap.warwick.ac.uk/id/eprint/36431

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