Molecular dynamics simulations of tensile testing have been performed on nc-SiC. Reduction of grain size promotes simultaneous enhancement of ductility, toughness, and strength. nc-SiC fails by intergranular fracture preceded by atomic level necking. Conventionally, high strain-rate deformations of ceramics are limited by diffusion time scales, since diffusion prevents premature cavitation and ...

We introduce a continuum approach to studying the lifetimes of monovalent metal nanowires. By modelling the thermal fluctuations of cylindrical nanowires through the use of stochastic Ginzburg-Landau classical field theories, we construct a self-consistent approach to the fluctuation-induced “necking” of nanowires. Our theory provides quantitative estimates of the lifetimes for alkali metal nan...

We present a general framework to explore thermally activated failures in quasi-one-dimensional systems. We apply it to the collapse of carbon nanotubes, the formation of bottlenecks in nanowires, both of which affect conductance, and the opening of local regions or "bubbles" of base pairs in strands of DNA that are relevant for transcription and denaturation. We predict an exponential behavior...

We report molecular dynamics simulations of the recently discovered superelongation of carbon nanotubes (CNTs) at high temperatures. The nearly simultaneous activation and wide distribution of a large number of defects near the elastic limit play a key role in impeding the formation of localized predominant instability and facilitating large tensile elongation. It suggests new and more complex ...

There are several characteristics of silver agglomerates that are not incorporated in existing models for agglomerate dynamics. These characteristics include particle alignment in the electric field, necking between particles, polydispersity of the primary particles, and variable primary sphere size. Estimates of these features on the agglomerate dynamics were computed as perturbations to the C...

Abstract The forming limit diagram (FLD) of high-purity niobium sheets used for the manufacturing superconducting radiofrequency (SRF) cavities is presented. Marciniak (in-plane) test was with blanks a thickness 1 mm and blank carriers annealed oxygen-free electronic (OFE) copper. A high formability measured, an approximate true major strain at necking plane 0.44. likely caused by its rate sens...

To enable an accurate simulation of manufacturing processes, it is essential to characterise and model the mechanical behaviour sheet metals up large deformations. However, after onset necking, deformation becomes highly heterogeneous stress triaxial. By combining full-field measurements inverse methods, possible calibrate beyond necking. A possibility use virtual fields method, by extending it...