The role of grain-boundary (GB) in the melting for Sigma=5 bicrystals of B2 NiAl is investigated by molecular-dynamics simulation. The thermodynamic properties of the boundary are monitored over a wide temperature ran...The role of grain-boundary (GB) in the melting for Sigma=5 bicrystals of B2 NiAl is investigated by molecular-dynamics simulation. The thermodynamic properties of the boundary are monitored over a wide temperature range including the thermodynamic melting point T-m which is determined by using a many-body potential fitted to NiAl. A thermal disorder transition in the GB region occurs well below the melting point. Our results indicate that such a transition is a continuous process and there is no evidence of premelting, which is entirely in accord with experimental results and theoretical prediction. Moreover, we also find that the superheated temperature range of this intermetallic alloy is much wider than that of some elemental metals.展开更多
The effect of boron-on carbide morphology of high Cr ledeburite steel has been studied. The results showed that B had obvious influence on eutectic carbide morphology in solidification structure and carbide granulatio...The effect of boron-on carbide morphology of high Cr ledeburite steel has been studied. The results showed that B had obvious influence on eutectic carbide morphology in solidification structure and carbide granulation at high temperature. The addition of 0.02 similar to 0.05 wt pet B changed carbide morphology in solidification structure from strip eutectic and rosette eutectic into divorced eutectic. B accelerated carbide granulation through increasing unstability and lattice distortion of carbide and element diffusion, Granular carbide could be achieved when heated at 1150 degrees C for 1.5 h.展开更多
文摘The role of grain-boundary (GB) in the melting for Sigma=5 bicrystals of B2 NiAl is investigated by molecular-dynamics simulation. The thermodynamic properties of the boundary are monitored over a wide temperature range including the thermodynamic melting point T-m which is determined by using a many-body potential fitted to NiAl. A thermal disorder transition in the GB region occurs well below the melting point. Our results indicate that such a transition is a continuous process and there is no evidence of premelting, which is entirely in accord with experimental results and theoretical prediction. Moreover, we also find that the superheated temperature range of this intermetallic alloy is much wider than that of some elemental metals.
文摘The effect of boron-on carbide morphology of high Cr ledeburite steel has been studied. The results showed that B had obvious influence on eutectic carbide morphology in solidification structure and carbide granulation at high temperature. The addition of 0.02 similar to 0.05 wt pet B changed carbide morphology in solidification structure from strip eutectic and rosette eutectic into divorced eutectic. B accelerated carbide granulation through increasing unstability and lattice distortion of carbide and element diffusion, Granular carbide could be achieved when heated at 1150 degrees C for 1.5 h.
