Use of Xray Diffraction on Bulk Metallic Glass

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SJSU Mate 144 Project
Marcus Samale
Use of X-ray Diffraction on Bulk Metallic Glass
produced with a prototype vacuum sealed arc
melting/drop casting/suction casting furnace
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The Furnace
Schematic drawing of prototype for an arc melting
furnace capable of combination drop / suction
casting
Actual prototype in Boston
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Goal of X-Ray Diffraction of Bulk Metallic Glasses
Avoid This!
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Results of the X-Ray Diffraction of Bulk Metallic
Glass Rod 1
Samples from 3 sections of the as cast rod. Top,
middle, bottom.
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Results of the X-Ray Diffraction of Bulk Metallic
Glass Rod 2
Samples from 3 sections of the as cast rod. Top,
middle, bottom.
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Use of XRD in Probing the Structure of Glasses
Basics of amorphous XRD Short range order causes
broad of peaks due to differing orientations of
bonds relative to the surface.
Methodology ? Take XRD data of sample ? Correct
Intensity data for errors (Polarization, Compton
scattering etc) ? Calculate the total reduced
interference function F(Q) from I(Q) Q
4psin(?) / ? ? Apply the Fourier Transform to
F(Q) gives us the total reduced radial
distribution function. ? G(r) ?wijGij(r)
wij cicjfifj / (cjfj cjfj )2
Gij partial correlations wij weighting
factor ci atomic fraction fi
complex atomic scattering factor ? Fit with
Gaussian Functions or do a Reverse Monte Carlo
routine
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References
J.J. Wall, C. Fan, P.K. Liaw, C.T. Liu, H. Choo.
2006. A combined drop/suction-casting machine for
the manufacture of bulk-metallic-glass materials.
Review of Scientific Instruments 77, 033902
Masaaki Yamada, Hiroshi Kitaguchi, Kazuhide
Tanaka. 2004. Magnetic properties and X-ray
structure analyses of NdCoB amorphous alloys.
Materials Science and Engineering A 375377
11651168