Thermal structural disorder and melting at a crystalline interface.
Thermal structural disorder and melting at a crystalline interface.
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晶体界面处的热结构无序和熔化。
DOI：
10.1103/physrevb.46.6050
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
Yip
中科院分区：
文献类型：
--
作者：
Nguyen;Ho;Kwok;Nitta;Yip
Thermal disordering and melting at a grain boundary are investigated by molecular dynamics in an internally consistent simulation model that avoids a number of pitfalls of earlier models. The bulk melting temperature ${\mathit{T}}_{\mathit{m}}$ of the model system, specified by an embedded-atom-method potential function fitted to aluminum, is first determined by observing directly surface-nucleated melting in a single-crystal cell with free surfaces. Simulation is then carried out on a bicrystal cell with a high-angle symmetrical tilt grain boundary on the (1\ifmmode\bar\else\textasciimacron\fi{}30) plane. Profiles across the interface of local structural order and energy, along with data on atomic mobility, are obtained at several temperatures from below ${\mathit{T}}_{\mathit{m}}$ to above ${\mathit{T}}_{\mathit{m}}$; the results indicate that melting is nucleated at the grain boundary in a similar manner as at the free surface, and that there is no evidence of premelting. In the surface region as well as the grain-boundary core, thermal disordering at temperatures below ${\mathit{T}}_{\mathit{m}}$ was observed with characteristic metastable behavior commencing at about 0.93 ${\mathit{T}}_{\mathit{m}}$. The temperature variation of the interfacial thickness suggests that the onset of disordering is a continuous process.
Thermal disordering and melting at a grain boundary are investigated by molecular dynamics in an internally consistent simulation model that avoids a number of pitfalls of earlier models. The bulk melting temperature ${\mathit{T}}_{\mathit{m}}$ of the model system, specified by an embedded-atom-method potential function fitted to aluminum, is first determined by observing directly surface-nucleated melting in a single-crystal cell with free surfaces. Simulation is then carried out on a bicrystal cell with a high-angle symmetrical tilt grain boundary on the (1\ifmmode\bar\else\textasciimacron\fi{}30) plane. Profiles across the interface of local structural order and energy, along with data on atomic mobility, are obtained at several temperatures from below ${\mathit{T}}_{\mathit{m}}$ to above ${\mathit{T}}_{\mathit{m}}$; the results indicate that melting is nucleated at the grain boundary in a similar manner as at the free surface, and that there is no evidence of premelting. In the surface region as well as the grain-boundary core, thermal disordering at temperatures below ${\mathit{T}}_{\mathit{m}}$ was observed with characteristic metastable behavior commencing at about 0.93 ${\mathit{T}}_{\mathit{m}}$. The temperature variation of the interfacial thickness suggests that the onset of disordering is a continuous process.