A combined Monte Carlo-damped trajectory simulation of nanometric testing of fcc metals under uniaxial tension

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Abstract
Nanometric uniaxial tension tests have been conducted on four fcc metals, namely, Al, Cu, Ag and Ni using combined Monte Carlo (MC)-damped trajectory (DT) simulations and the results compared with conventional MD simulations employing the same potential-energy surface and identical testing conditions. The MC-DT method combines DTs or steepest-descent methods with MC-Markov chains to converge the lattice atom coordinates rapidly to those that characterize the equilibrium state for a given extension of the workpiece in the tensile test. The computational times required for the MC-DT method are significantly less than the corresponding times for pure MD simulations; they are nearly a linear function of the number of lattice atoms for the MC-DT calculation, but exponential for the MD studies. This differential becomes significant as the number of atoms under consideration increases. Ultimate strengths and the corresponding strains, Young's modulus, and the strain at fracture are nearly in the same ranking order as the intrinsic strength and ductility of these materials and agree reasonably well with the theoretical strength calculations as well as with pure MD simulations.