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In current study molecular dynamics (MD) simulations are performed to reveal effects of pre-existing defects on nanoimprint of single crystal aluminum () thin films. Simulation results suggest that critical force required for plastic deformation initiation decreases with the increase of vacancy volume fraction, but increases with the interstitial volume fraction. It is found that adsorption phenomenon is affected by pre-existing defects, as adsorption phenomenon weakens with the increasing interstitial volume fraction. Pre-existing defects have significant influence on the deformation mechanisms and imprint forces during the nanoimprint processes. Simulation results also show that surface deformation is strongly affected by pre-existing defects. [ABSTRACT FROM AUTHOR]

Abstract: Molecular dynamics simulations were performed to elucidate the mechanisms of deformation in bi-crystal Al thin films with twin boundaries subjected to the nanoimprint process. The effects of stamp spacing on deformation behavior and the mechanical response of the imprinted material were examined. Simulation results indicated that dislocation activity and dislocation–TB interaction are two plastic deformation modes in bi-crystal Al thin films. The results demonstrated that the stamp spacing has significant influence on the dislocation–TB interaction during the nanoimprint process. [Copyright &y& Elsevier]

Abstract: Pre-existing defects can alter mechanical behavior of materials significantly under applied load. In current study molecular dynamics (MD) simulations are performed to reveal pre-existing void effect on nanoimprint of single crystal Al thin films, such as deformation mechanism and spring back phenomenon. Current simulation results show void acts as strong barrier to dislocation motion, although plastic deformation is dominantly controlled by dislocation activities. It indicates the void volume fraction has strong influence on nanoimprint: the larger the void volume fraction, the smaller the maximum force required for initial dislocation nucleation, and the stronger the interaction between extended dislocation and void. It also demonstrates that there is a critical void volume fraction for minimum spring back, which is resulted from competition between two roles affecting dislocation annihilation. [Copyright &y& Elsevier]