Nanotwinned metals are attractive in many applications because they simultaneously demonstrate high strength and high ductility, characteristics that are usually thought to be mutually exclusive. However, most nanotwinned metals are produced in polycrystalline forms and therefore contain randomly oriented twin and grain boundaries making it difficult to determine the origins of their useful mec...

Shock-induced spall in ductile metals is known to occur by the sequence of nucleation, growth and coalescence of voids, even in high purity monocrystals. However, the atomistic mechanisms involved are still not completely understood. The growth and collapse of nanoscale voids in tantalum are investigated under different stress states and strain rates by molecular dynamics (MD) simulations. Thre...

We present a comprehensive computational analysis of the deformation of ultrafine crystalline pure Cu with nanoscale growth twins. This physically motivated model benefits from our experimental studies of the effects of the density of coherent nanotwins on the plastic deformation characteristics of Cu, and from post-deformation transmission electron microscopy investigations of dislocation stru...

Recent studies have shown that nanotwinned copper (NT Cu) exhibits a combination of high strength and moderate ductility. However, most engineering and structural applications would also require materials to have superior fracture toughness and prolonged subcritical fatigue crack growth life. The current study investigates the effect of twin density on the crack initiation toughness and stable ...

Nanocrystalline 3mm thick Cu1–xNix (0.45 £ x £ 0.87) films are electrodeposited galvanostatically onto Cu/Ti/Si (100) substrates, from a citrateand sulphate-based bath containing sodium lauryl sulphate and saccharine as additives. The films exhibit large values of reduced Young’s modulus (173< Er< 192GPa) and hardness (6.4<H< 8.2GPa), both of which can be tailored by varying the alloy compositi...

High density grain boundaries provide high strength, but may introduce undesirable features, such as high Fermi levels and instability. We investigated the kinetics of recovery and recrystallization of Cu that was manufactured to include both nanotwins (NT) and high-angle columnar boundaries. We used the isothermal Johnson-Mehl-Avrami-Kolmogorov (JMAK) model to estimate activation energy values...

Despite the extensive investigation on the structure of natural biological materials, insufficient attention has been paid to the structural imperfections by which the mechanical properties of synthetic materials are dominated. In this study, the structure of bivalve Saxidomus purpuratus shell has been systematically characterized quantitatively on multiple length scales from millimeter to sub-...

We have performed in situ scanning electron microscopy tensile experiments and molecular dynamics (MD) simulations on nominally defect-free single-crystalline Au nanowhiskers. The room temperature experiments reveal strengths on the order of the ideal strength and plastic strains of up to 12%, a direct result of deformation twinning that governs plastic flow. The in situ and post mortem electro...

The morphologies and microstructures of kinked InP nanowires (NWs) prepared by solid-source chemical vapor deposition method were examined using scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). Statistical analysis and structural characterization reveal that four different kinds of kinks are dominant in the grown InP NWs with a bending angle of ap...