Nanowires: The long and short of breaking

Most materials will break when a force is applied to an imperfection in their structure -- such as a notch or dislocation. The behavior of these imperfections, and the resulting breakage, differ markedly between small structures, such as nanowires, and larger, bulk materials. However, scientists lacked complete understanding of the precise mechanics of nanowire breakages, owing in part to inconsistent behavior in experiments. These inconsistencies are now resolved thanks to numerical simulations by Zhaoxuan Wu and his co-workers at the A*STAR Institute for High Performance Computing, Singapore, and collaborators in the USA1.

The researchers focused on metal nanowires with a so-called 'face-centered cubic crystal structure' because they exhibit two different failure modes. Previous experiments by other groups showed that these nanowires can break as the result of a ductile process, in which a narrow neck is formed smoothly and continuously before failure. Other experiments showed that the failure was caused by a brittle fracture, which happened suddenly. To complicate matters further, atom-scale simulations of these experiments predicted that only ductile necking should be occurring.

Most materials will break when a force is applied to an imperfection in their structure -- such as a notch or dislocation. The behavior of these imperfections, and the resulting breakage, differ markedly between small structures, such as nanowires, and larger, bulk materials. However, scientists lacked complete understanding of the precise mechanics of nanowire breakages, owing in part to inconsistent behavior in experiments. These inconsistencies are now resolved thanks to numerical simulations by Zhaoxuan Wu and his co-workers at the A*STAR Institute for High Performance Computing, Singapore, and collaborators in the USA (1).

The researchers focused on metal nanowires with a so-called 'face-centered cubic crystal structure' because they exhibit two different failure modes. Previous experiments by other groups showed that these nanowires can break as the result of a ductile process, in which a narrow neck is formed smoothly and continuously before failure. Other experiments showed that the failure was caused by a brittle fracture, which happened suddenly. To complicate matters further, atom-scale simulations of these experiments predicted that only ductile necking should be occurring.

The A*STAR-affiliated researchers contributing to this research are from the Institute for High Performance Computing.