Effect of Grain Boundary Melting on Sliding in Bicrystals: a Molecular Dynamics Study
نویسنده
چکیده
Grain boundaries arc known to exert a profound influence on the properties of polycrystalline materials at high temperature. Experimental studies on grain boundary sliding in Al bicrystals (I), or more recently in Zn bicrystals (2), show a change in the temperature dependence of the sliding rate at temperatures between 70% to 90% of the bulk melting point. The critical temperature at which a change in activation energy for sliding occurs depends to a large extent on the grain boundary type. Coincidence grain boundaries exhibit the highest critical temperatures. It has been suggested that the observed change in the temperature dependence of the sliding rate may be caused by a grain boundary phase transition tslring place at the critical temperature (2). The exact nature of this grain boundary phase transition is, however, still unresolved. Many difficulties associated with the small size of the grain boundary region make the cxperirnental investigation of grain boundary phase transitions cumbersome. On the other hand, atomistic computer simulation has been proved to be a very handy technique for the correlation of macroscopic properties to structural properties. In this letter we present molecular dynamics results on grain boundary sliding in a three dimensional Lennard-Jones bicrystal.
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