Compressive pseudoelastic behavior in copper nanowires
S Lee and B Lee and M Cho, PHYSICAL REVIEW B, 81, 224103 (2010).
We predict the pseudoelasticity of the < 100 >/100 copper nanowire using atomistic simulations with the embedded atom method potential under uniaxial compressive loading. The < 100 >/100 copper nanowire exhibits pseudoelasticity which depends on the reorientation of the crystalline structure of the nanowire due to twinning. The twinning that governs the pseudoelasticity of the < 100 >/100 nanowire results from an external compressive loading whereas the twinning that governs the pseudoelasticity of the < 100 >/100 nanowire results from a tensile loading. Therefore, the pseudoelasticity of the < 100 >/100 nanowire is referred to as "compressive pseudoelasticity." This difference in the twinning phenomena distinguishes the < 100 >/100 nanowire from the < 100 >/100 nanowire. This study also shows that the pseudoelasticity of the nanowire is related to the stacking-fault energy of the nanowire material and the Schmid factor which depends on the structural orientation of the nanowire. The < 100 >/100 nanowire shows the maximum recoverable strain of 22% which is a remarkable amount compared with 5 - 10 % for bulk shape memory alloys. In addition, the < 100 >/100 nanowire does not need to reach the critical temperature to exhibit pseudoelasticity because the lateral free surfaces of the twin region have lower energy than the surface of the nanowire.
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