Effects of Dopants on the Mechanical Properties of Nanocrystalline Silicon Carbide Thin Film
Liming Xiong; and Youping Chen

Source CMES: Computer Modeling in Engineering & Sciences, Vol. 24, No. 3, pp. 203-214, 2008
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Keywords nanocrystalline ceramics, silicon carbide, atomistic field theory, dopants
Abstract This paper presents the application of an atomistic field theory (AFT) in modeling and simulation of boron- , boron/nitrogen and silicon/nitrogen-doped nanocrystalline silicon carbide (B-, BN-, SiN-SiC). Intergranular glassy films (IGFs) and nano-sized pores have been obtained in triple junctions of the grains in nanocrystalline SiC (nc-SiC). Residual tensile stress in the SiC grains and compressive stress in the grain boundaries (GBs) are observed. Under uniaxial tension, the constitutive responses of nanocrystalline SiC were reproduced from the simulations. It is found that the mechanical properties of nanocrystalline SiC are strongly dependent on the compositions of GBs. Although there are more nano-sized pores in the triple junctions of the grains, interestingly, compared with B-Si and BN-SiC, SiN-SiC exhibits the highest strength. Numerically, for crystalline materials, it has been shown that AFT can be naturally reduced to atomic-level simulation when the finite element meshes is reduced to the network of lattice.
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