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The Structure of Nanocrystalline Iron and Tungsten Powders Prepared by High-Energy Ball Milling

Published online by Cambridge University Press:  06 March 2019

C.N.J. Wagner ,
E. Yang  and
M.S. Boldrick
C.N.J. Wagner
Affiliation:
Department of Materials Science and Engineering University of California, Los Angeles Los Angeles, CA 90024-1595, USA
E. Yang
Affiliation:
Department of Materials Science and Engineering University of California, Los Angeles Los Angeles, CA 90024-1595, USA
M.S. Boldrick
Affiliation:
Department of Materials Science and Engineering University of California, Los Angeles Los Angeles, CA 90024-1595, USA
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Abstract

Nanocrystalline powders of Fe and W were prepared by mechanical working in a highenergy Spex 8000 mixer/mill. The diffraction patterns were recorded with Co Kα radiation and the line profiles were subjected to a Fourier analysis. The size 〈D〉 of the coherently diffracting domains (x-ray particle size) and the root-mean square strains 〈ε2L〉1/2 were determined with the Warren-Averbach method. In addition, the integral breadths were evaluated and corrected for instrumental broadening assuming Cauchy line profiles. In order to separate particle size and strains, the corrected breadths β(s) = βcosθ/λ were plotted as a function of s = 2sinθ/λ, i.e., β(s) =(1/D) + 2ε s, where D = 〈D2/〈D〉 and ε is a strain averaged over the domain size D.

X-ray fluorescence analysis indicated that the W powders contained an iron and chromium contamination due to the abrasion of the stainless steel balls reaching a value of 24 at% Fe+Cr after 20h of milling. Since W is elastically isotropic, all available (hkl) reflections can be used in the Warren-Averbach and line breaddi analyses. After 20 h of milling, the W powder exhibited a particle size 〈D〉 = 35 Å and a strain 〈ε2〉1/2 = 0.52% at L = 30 Å. The integral breadths yielded the particle size D1 = 70 Å and the strain ε = 0.38%. in the case of Fe powder, also milled for 20 h, the (110) - (220) pair of reflections was used to calculate the particle size and strains. The Fourier analysis yielded the values 〈D〉 = 105 Å and 〈ε2〉1/2 = 0.59% at L = 30 Å. The corresponding integral breadth values are D1 = 280 Å and ε1 = 0.7%. The sum of the particle size Fourier coefficients is equal to the integral breadth particle size D1 = 125 Å, which is very close to value 〈D〉 = 105 Å indicating that the particle or domain sizes have a very narrow size distribution.

Type
VIII. XRD Profile Fitting, Crystallite Size and Strain Determination
Information
Advances in X-Ray Analysis , Volume 35 , Issue A: First Pacific-International Congress on X-ray Analytical Methods (PICXAM). Fortieth Annual Conference on Applications of X-ray Analysis, August 7-16, 1991 , 1991 , pp. 585 - 592
Copyright
Copyright © International Centre for Diffraction Data 1991

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References

Birringer, R., and Gleiter, H., 1988, in "Encyclopedia of Materials Science", R.W. Cahn, ed., Suppl. Vol. 1 Pergamon Press, p. 339.Google Scholar
Calka, A., and Radlinski, A.P., 1991, Universal high performance ball-milling device and its application for mechanical alloying, Mat. Sci. Engr., A134: 1350.Google Scholar
Fecht, H., Hellstern, E., Fu, Z., and Johnson, W.L., 1990, Nanocrystalline Metals Prepared by High-Energy Ball Milling, Met. Trans.A. 21 A: 2333.Google Scholar
Gaffet, E., Louison, C. Harmelin, M., and Faudot, F., 1991, Metastable phase transformations introduced by ball-milling in die Cu-W system, Mat Sci, Engr,. Al34: 1380.Google Scholar
Guinier, A., 1963, "X-Ray Diffraction", W.H. Freeman and Company, San Francisco.Google Scholar
Haider, N.C., and Wagner, C.N.J., 1966, Analysis of the Broadening of Powder Pattern Peaks Using Variance, Integral Breadth, and Fourier Coefficients of the Line Profile, Adv. X-Ray Analysis, 9: 91.Google Scholar
Hellstern, E., Fecht, H.J., Fu, Z., and Johnson, W.L., 1989, Structural and thermodynamic properties of heavily mechanically deformed Ru and AlRu, J. Appl, Phys., 65: 305.Google Scholar
Oehring, M. and Bormann, R., 1991, Nanocrystalline alloys prepared by mechanical alloying and ball milling, Mat. Sci. Engr., A134:1330.Google Scholar
Trudeau, M.L., and Schulz, R., 1991, High-resolution electron microscopy study of Ni-Mo nanocrystals prepared by high-energy mechanical alloying, Mat. Sci. Engr,. A134: 1361.Google Scholar
Wagner, C.N.J., 1966, Analysis of the Broadening and Changes in Position in an X-Ray Powder Pattern, in :"Local Atomic Arrangements Studied by X-Ray Diffraction", Cohen, J.B. and Hilliard, I.E., eds., Met. Soc. Conf. Vol 36, p. 219.Google Scholar
Wagner, C.N.J., and Aqua, E.N., 1964, Analysis of the Broadening of Powder Pattern Peaks from Cold-Worked Pace-Centered and Body-Centered Cubic Metals, Adv. X-Ray Analysis. 7:46.Google Scholar
Wagner, C.N.J., and Aqua, E.N., 1967, Faulting in Cold-Worked Fe-Si Alloy Filings, Trans. Met. Soc. AIME. 239: l00l.Google Scholar
Wagner, C.N.J., Boldrick, M.S., and Keller, L., 1988, Micro structural Characterization of Thin Polycrystalline Films by X-ray Diffraction. Adv. X-Rav Analysis, 31: 129.Google Scholar
Warren, B.E., 1969, "X-Ray Diffraction", Addison-Wesley Publishing Company, Reading.Google Scholar