Molecular Dynamics Study of Grain-Boundary-Induced Melting in B2 NiAl Using a Many-body Potential

The role of grain-boundary (GB) in the melting for ∑=5 bicrystals of B2 NiAl is investigatedby molecular-dynamics simulation. The thermodynamic properties of the boundary are moni-tored over a wide temperature range including the thermodynamic melting point Tm, which isdetermined by using a many-body potential fitted to NiAl. A thermal disorder transition in theGB region occurs well below the melting point. Our results indicate that such a transltion isa 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.