Computer Simulations of Diffraction Effects due to Stacking Faults in β-SiC: I, Simulation Results

Autor: James D. Cawley, Vijay V. Pujar
Rok vydání: 2005
Předmět:
Zdroj: Journal of the American Ceramic Society. 80:1653-1662
ISSN: 1551-2916
0002-7820
DOI: 10.1111/j.1151-2916.1997.tb03034.x
Popis: X-ray diffraction (XRD) patterns from nominally β-SiC specimens often differ from those expected for the cubic crystal structure. These differences include the presence of additional peaks, enhanced background intensities, peak broadening, changes in relative peak heights, and shifts in peak positions. It has long been recognized that they are due to the presence of stacking faults, and models relating the experimental observations to stacking fault population have continued to evolve. The presence and relative magnitude of these features vary among different β-SiC specimens. In this work, computer simulations were used to show that the variations are closely related to differences in the type and spatial distribution of stacking faults in each specimen. In these simulations, stacking sequences were generated using a selectively activated 1-D Ising model with a Boltzmann-type probability function for specifying errors, which allows a wide variety of fault configurations to be generated. Direct correlations between different features in the XRD data to the underlying fault population are demonstrated, which are discussed in this paper. It is also shown that this computer model is general, in the sense that many of the models presented in prior work can be interpreted as limiting cases of it.
Databáze: OpenAIRE
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