Nanowire failure: long = brittle and short = ductile.
Experimental studies of the tensile behavior of metallic nanowires show a wide range of failure modes, ranging from ductile necking to brittle/localized shear failure-often in the same diameter wires. We performed large-scale molecular dynamics simulations of copper nanowires with a range of nanowire lengths and provide unequivocal evidence for a transition in nanowire failure mode with change in nanowire length. Short nanowires fail via a ductile mode with serrated stress-strain curves, while long wires exhibit extreme shear localization and abrupt failure. We developed a simple model for predicting the critical nanowire length for this failure mode transition and showed that it is in excellent agreement with both the simulation results and the extant experimental data. The present results provide a new paradigm for the design of nanoscale mechanical systems that demarcates graceful and catastrophic failure.
Institute of High Performance Computing, 1 Fusionopolis Way, #16-16 Connexis, Singapore 138632.
Zhaoxuan
Z
Wu
Yong-Wei
YW
Zhang
Mark H
MH
Jhon
Huajian
H
Gao
David J
DJ
Srolovitz
D003300:Copper / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D053770:Nanowires / Q000737:chemistry*; D013499:Surface Properties
D003300:Copper