Interface migration in aluminum bicrystals via premelting

Abstract

We investigate solid-solid phase transformation and migration of interface between ambient and strained crystal of Al using molecular dynamics simulation by means of premelting. In agreement with previous observations both Al(100) and Al(110) exhibit premelting near melting temperature and strain enhance the thickness of melt irrespective to sign. In bicrystal of Al, if one of crystal is subjected to strain then internal stresses completely relax during premelting and additionally provides thermodynamic driving force. This melt recrystallise into ambient crystal in pico seconds. The propagating interface velocity as function of temperature and strain both are quantitatively measured. Two types of interface propagation is observed, for thin interfacial melt (two times of lattice constant or less) interface migration is not continuous it is stickslip and stochastic, and for thick premelted layer interface migration is barrier less. The results obtained are applicable to many structural changes like grain evolution, twinning, fracture and dislocations, phase transformation such as melting-solidification and solid-solid.