Molecular dynamics study of size, temperature and strain rate effects on mechanical properties of gold nanofilms

Y Gan and JK Chen, APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING, 95, 357-362 (2009).

DOI: 10.1007/s00339-008-4970-8

Temperature and extremely-high strain rate effects on mechanical properties of different-size gold nanofilms are investigated using molecular dynamics simulation. The numerical results clearly show a temperature softening effect on the material strength and Young's modulus and demonstrate a critical film thickness that characterizes a transition from "smaller is softer" to "smaller is stronger". It is also found that a higher strain rate yields a higher strength, whereas the modulus is much less sensitive to the loading rate. In addition, the Young's modulus and strength of nanofilms studied are approximately 50%-60% smaller and 50-90 times higher than those of bulk gold, respectively. This suggests that the use of the mechanical properties of a bulk material in a continuum-based approach might be inadequate for the accurate prediction of the thermomechanical response for gold nanofilms caused by ultrashort-pulsed laser heating.

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