Strain hardening capability is critical for metallic materials to achieve high ductility during plastic deformation. A majority of nanocrystalline metals, however, have inherently low work hardening capability with few exceptions. Interpretations on work hardening mechanisms in nanocrystalline metals are still controversial due to the lack of in situ experimental evidence. Here we report, by us...

A two phase microstructure, consisting of nanocrystallites surrounded by an amorphous matrix, was produced by a melt spinning processing route. Alloys of this type have extrinsic properties that are dependent on the relative amounts of the amorphous and nanocrystalline phases. One method for examination of the properties of the nanocrystalline and amorphous phases is by Mössbauer spectroscopy. ...

Here we explored the possibility of using CuInS2-based nanocrystals as colour converting materials for light-emitting applications. Using a mixture of red and green emissive CuInS2-based nanocrystals, we successfully fabricated high colour rendering white light-emitting diodes with surface mounted devices and high-power types. The devices exhibit improved luminous efficiency, high colour render...

Small molecular reagents that can efficiently functionalize water soluble CdSe/ZnS nanocrystals (NCs) are reported. These reagents do not cause quenching or precipitation of NCs as seen with commercially available activators. The results demonstrate that controlling the electrostatic character of the materials is critical in the design of functionalization schemes.

In this review, we highlight the progress made in the development of 4D ultrafast electron diffraction (UED), crystallography (UEC), and microscopy (UEM) with a focus on concepts, methodologies, and prototypical applications. The joint atomic-scale resolutions in space and time, and sensitivity reached, make it possible to determine complex transient structures and assemblies in different phase...

The process of second harmonic generation (SHG) has a unique property of forming a sharp optical contrast between noncentrosymmetric crystalline materials and other types of material, which is a highly valuable asset for contrast microscopy. The coherent signal obtained through SHG also allows for the recording of holograms at high spatial and temporal resolution, enabling whole-field four-dime...

The phonon density of states of nanocrystalline bcc Fe and nanocrystalline fcc Ni3Fe were measured by inelastic neutron scattering in two different ranges of energy. As has been reported previously, the nanocrystalline materials showed enhancements in their phonon density of states at energies from 2 to 15 meV, compared to control samples composed of large crystals. The present measurements wer...

Ingots of the bulk metallic glass (BMG), Zr64.13Cu15.75Ni10.12Al10 in atomic percent (at. %), are compressed at slow strain rates. The deformation behavior is characterized by discrete, jerky stress-drop bursts (serrations). Here we present a quantitative theory for the serration behavior of BMGs, which is a critical issue for the understanding of the deformation characteristics of BMGs. The me...

Research on ultrathin nanomaterials is one of the fastest developing areas in contemporary nanoscience. The field of ultrathin one- (1D) and two-dimensional (2D) colloidal nanocrystals (NCs) is still in its infancy, but offers the prospect of production of ultrathin nanomaterials in liquid-phase at relatively low costs, with versatility in terms of composition, size, shape, and surface control....

It is believed that the dynamics of dislocation processes during the deformation of nanocrystalline materials can only be visualized by computational simulations. Here we demonstrate that observations of dislocation processes during the deformation of nanocrystalline Ni with grain sizes as small as 10 nm can be achieved by using a combination of in situ tensile straining and high-resolution tra...