Stress-relaxation experiments were performed on nanotwinned Cu to characterize the twin size-dependence of the activation volume and mobile dislocation density. We find that the variation of activation volume as a function of twin lamellae thickness can be captured well by a Hall–Petch-type relation. This structure size-dependence is interpreted to arise from a transition of the rate-controllin...

The growth in investment on the effect of size in nanoscience and nanotechnology has been astounding. Of the $12.4B spent in 2006 worldwide Nanotechnology research funding [1], at least 50 % was spent on the effect of size for the development of nanomaterials and devices. The focus of nanoscience is to understand the influence of size on the material properties, while nanotechnology focuses on ...

The microstructure of deformation-processed metal-metal composites (DMMC) of Mg-Li alloys containing steel reinforcing fibers was characterized to correlate the fiber size to the deformation strain and mechanical properties of the composite material. Micrographs taken using scanning and transmission electron microscopy techniques revealed fiber sizes larger than predicted from the deformation a...

The characterization and measurement of grain structures is of great importance to materials scientists because not only does grain size strongly affect the mechanical properties, but it also has an influence on physical properties, surface properties and phase transformations [1]. The ability to locate the grain boundaries in materials is critical for a wide number of applications, e.g. proces...

In this investigation, special consideration was given to observe the influence of the acquired ultra-fine-grain (UFG) structure through friction stir processing (FSP) on mechanical and damping properties. As the mechanical behaviour of the composites are intensely related to their microstructure. For deeply understanding the possible mechanism and detailed microstructural observations at a lon...

In recent years, near-nano (submicron) and nanostructured materials have attracted increasingly more attention from the materials community. Nanocrystalline materials are characterized by a microstructural length or grain size of up to about 100 nm. Materials having grain size of 0.1 to 0.3 mm are classified as submicron materials. Nanocrystalline materials exhibit various shapes or forms, and ...

The influence of the ratio between specimen thickness (t) and grain size (D) on tensile fatigue properties plain notched aluminium plate specimens has been studied. Grain sizes ranging from 66 μm to 9.74 mm have prepared used in tests. observed decrease when D is comparable, or even exceeds, t can be accounted for by adding an additional negative exponential term Hall–Petch equation. An also fo...