Orientation and strain rate dependent tensile behavior of single crystal titanium nanowires by molecular dynamics simulations

L Chang and CY Zhou and HX Liu and J Li and XH He, JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY, 34, 864-877 (2018).

DOI: 10.1016/j.jmst.2017.03.011

Molecular dynamics simulation was employed to study the tensile behavior of single crystal titanium nanowires (NWs) with 11 (2) over bar0, (1) over bar 100 and 0001 orientations at different strain rates from 10(8) s(-1) to 10(11) s(-1). When strain rates are above 10(10) s(-1), the state transformation from HCP structure to amorphous state leads to super plasticity of Ti NWs, which is similar to FCC NWs. When strain rates are below 10(10) s(-1), deformation mechanisms of Ti NWs show strong dependence on orientation. For 11 (2) over bar0 orientated NW, 10 (1) over bar1 compression twins (CTs) and the frequently activated transformation between CTs and deformation faults lead to higher plasticity than the other two orientated NWs. Besides, tensile deformation process along 11 (2) over bar0 orientation is insensitive to strain rate. For (1) over bar 100 orientated NW, prismatic < a > slip is the main deformation mode at 108 s(-1). As the strain rate increases, more types of dislocations are activated during plastic deformation process. For 0001 orientated NW, 10 (1) over bar2 extension twinning is the main deformation mechanism, inducing the yield stress of 0001 orientated NW, which has the highest strain rate sensitivity. The number of initial nucleated twins increases while the saturation twin volume fraction decreases nonlinearly with increasing strain rate. (C) 2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of Materials Science & Technology.

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