Analysis of picosecond pulsed laser melted graphite
A Raman microprobe and high resolution TEM have been used to analyze the resolidified region of liquid carbon generated by picosecond pulse laser radiation. From the relative intensities of the zone center Raman-allowed mode for graphite at 1582 cm/sup -1/ and the disorder-induced mode at 1360 cm/sup -1/, the average graphite crystallite size in the resolidified region is determined as a function of position. By comparison with Rutherford backscattering spectra and Raman spectra from nonosecond pulsed laser melting experiments, the disorder depth for picosecond pulsed laser melted graphite is determined as a function of irradiating energy density. Comparisons of TEM micrographs for nanosecond and picosecond pulsed laser melting experiments show that the structure of the laser disordered regions in graphite are similar and exhibit similar behavior with increasing laser pulse fluence.
- Research Organization:
- Los Alamos National Lab., NM (USA); Massachusetts Inst. of Tech., Cambridge (USA); Harvard Univ., Cambridge, MA (USA)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 6973903
- Report Number(s):
- LA-UR-86-4339; CONF-861207-45; ON: DE87003755
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
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75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CARBON
ELECTROMAGNETIC RADIATION
ELECTRON MICROSCOPY
ELEMENTS
FLUIDS
LASER RADIATION
LASER SPECTROSCOPY
LIQUIDS
MELTING
MICROSCOPY
NONMETALS
PHASE TRANSFORMATIONS
RADIATIONS
RAMAN SPECTROSCOPY
SOLIDIFICATION
SPECTROSCOPY