Abstract
To investigate effects of Ce doping on anisotropy and mechanical properties of M7C3 (Fe3Cr4C3) carbides in hypereutectic Fe–Cr–C hardfacing alloy, the stability, anisotropic elastic moduli, intrinsic hardness, tensile property and electronic structures of Ce-doped M7C3 (Fe3Cr3CeC3) carbide were calculated by first principles method. The element distribution and nano indentation experiments were used to prove the reliability of the calculation rules. We found that the formation enthalpy of Fe3Cr3CeC3 is lower than that of Fe3Cr4C3, which indicates that Fe3Cr3CeC3 forms preferentially. No imaginary frequency appears in the phonon dispersion spectrums, which reveals that the crystal models used in calculations are stable. The anisotropy of elastic moduli is reduced by Ce atoms doping. Intrinsic hardness of Fe3Cr3CeC3 is decreased from 18.83 GPa to 6.64 GPa. Its fracture elongations on weak crystal faces are increased from 7% to 17%. The increase of tensile fracture elongation, as well as the decrease of intrinsic hardness, shows that ductility and toughness of M7C3 carbides can be improved by Ce doping. The nano indentation results also prove the ductility and toughness increase of Ce-doped M7C3 carbide. The improvement mechanism is electron redistribution and more stable chemical bonds formation caused by Ce atoms. This can provide a new idea and theoretical foundation for design and preparation of novel M7C3 reinforced hardfacing alloys with preferable mechanical properties.
Published Version
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