| Summary: | 碩士 === 國立中山大學 === 機械與機電工程學系研究所 === 103 === The mechanical properties and structural properties of Fe-Cr-C-Mo bulk metallic glasses have been investigated by molecular dynamics (MD) simulation with the 2NN modified embedded-atom method (2NN MEAM) potential which be used to model the atomic interactions among Fe, Cr, C, and Mo atoms. Furthermore, the reference data were obtained from the density functional theory (DFT) calculations. The parameter sets of binary element of Fe-Cr, Fe-Mo, Fe-C, Cr-Mo, Cr-C and Mo-C were fitted by force-matching (FM) method. Finally, these parameter sets of MEAM were further applied in generating Fe54Cr16Mo12C18 amorphous structures by basin-hopping (BH) method for conducting tensile simulations to get the stress-strain profiles. The mechanical properties and deformation mechanism, such as elastic modulus, plastic/elastic deformation mechanism and local strain distribution at different strains, were further investigated by the MD simulation.
According to stress-strain profiles, the estimated Young’s modulus of Fe54Cr16Mo12C18 bulk metallic glass is about 139 GPa. It also shows that this bulk metallic glass possess excellent ductility because of large plastic region. Local strain distribution was used to analyze the deformation mechanism, and the results reveal that shear bands form homogeneously and the tensile fracture angle (θT) is about 50 degree which is agreement with experimental result of 45°&;lt; θT &;lt; 90°. Finally, Honeycutt-Andersen (HA) index were used to investigate the plastic/elastic deformation mechanism of Fe54Cr16Mo12C18 BMG under the tensile test.
|
|---|
