In this research, we assessed the influence of an ultrafine 2CaO·SiO₂ powder on the hydration properties of a reactive powder concrete system. The ultrafine powder was manufactured through chemical combustion method. The morphology of ultrafine powder and the development of hydration products in the cement paste prepared with ultrafine powder were investigated by scanning electron microscopy (S...

Ultrafine composite fibers consisting of a thermoplastic polyurethane solid-solid phase-change material and organic lanthanide luminescent materials were prepared through a parallel electrospinning technique as an innovative type of ultrafine, dual-functional fibers containing phase-change and luminescent properties. The morphology and structure, thermal energy storage, and luminescent properti...

In the Ultra-steel project at the National Institute for Materials Science (NIMS), which run from 1996 to 2005, high-Si-Al-content ultrafine-grained (UFG) weathering steel was developed by grain refinement and weathering guidance. It was found that this steel has excellent strength, toughness and corrosion resistance. Samples were prepared by multi pass warm rolling at temperatures between 773 ...

An ultrafine/nano grained AZ31 magnesium alloy was produced through four-pass ECAP processing. TEM microscopy indicated that recrystallized regions included nano grains of 75 nm. Pole figures showed that a fiber basal texture with two-pole peaks was developed after four passes, where a basal pole peak lies parallel to the extrusion direction (ED) and the other ~20° away from the transverse dire...

Recent studies have shown that strength values similar to those observed in nanocrystalline metals can be obtained without a severe deterioration in ductility. This is achieved by introducing controlled, nanoscale, growth twins within ultrafine-grained metals. In this work, we present a continuum description of the effective response of nanotwinned ultrafine crystals. The model is based on a fi...

In the last three decades, several severe plastic deformation (SPD) procedures have been developed and applied in materials science to create bulk, ultrafine-grained (UFG) structures. As a consequence of SPD, not only submicron even nanometer grain sizes can be obtained, but also new boundaries with non-equilibrium structures material may formed. Therefore, both strength ductility UFG change si...

The exceptional strength and distinct deformation physics exhibited by pure ultrafine-grained and nanocrystalline metals in comparison to their microcrystalline counterparts have been ascribed to the dominant influence of grain boundaries in accommodating plastic flow. Such grain-boundary-mediated mechanisms can be augmented by additional strengthening in nanocrystalline alloys via solute and p...

The microstructural evolution of interstitial-free (IF) steel subjected to Φ = 90° Equal Channel Angular Extrusion (ECAE) for up to 4 passes via routes A, BA, C and up to 8 passes via routes BC was studied using Electron Back-Scatter Diffraction (EBSD). Routes BC and BA recorded the smallest grain size and aspect ratios and the largest average misorientation and area fraction of high-angle grai...

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 ...

Equal channel angular pressing (ECAP) was performed on ZK60 alloy and pure Mg in the temperature range 150-250 °C. A significant grain refinement was detected after ECAP, leading to an ultrafine grain size (UFG) and enhanced formability during extrusion process. Comparing to conventional coarse grained samples, fracture elongation of pure Mg and ZK60 alloy were significantly improved by 130% an...