Molecular dynamics study of strain rate effects on tensile behavior of single crystal titanium nanowire

Molecular dynamics simulations were performed to study the tensile behaviors of single crystal titanium nanowire along [ 0001] direction under different strain rates using the Finnis-Sinclair many-body potential. The applied strain rate is ranging from 108 s(-1) to 1011 s(-1) (0.0001-0.1 ps(-1)). At strain rates below 0.01 ps(-1), the stress-strain curves can be divided into four distinct stages: initial linear stage, sharp drop stage, rapid rise stage and wavelike decrease stage. Structural analysis reveals that the growth of f10 (1) over bar 2g tensile twin leads to the rapid rise stage in stress-strain curves. The evolution of twinning variants indicates that the number of nucleated twin variants increases with the applied strain rate and the overall twin volume fraction decreases with strain rate. At strain rates above 0.01 ps(-1), three distinct stages are observed in the stress-strain curves. At these strain rates, a rapid transformation to an amorphous state was observed leading to superplastic behavior of nanowire. Besides, deformation mechanism map was constructed for nanowire during tension process at different strain rates. (C) 2016 Elsevier B. V. All rights reserved.