During last two decades great attention was paid to materials with grains of diameter smaller than 1 μm. These materials were classified as Ultra Fine Grain (UFG) materials with diameter of grains of the order of 100 to 1000 nm and nano-materials with mean diameters of grains smaller than 50 nm. This research concerned the whole production of UFG materials, using Severe Plastic Deformation (SPD...

in the present study, an ultrafine grained (ufg) 304l stainless steel with the average grain size of 300 nm was produced by a combination of cold rolling and annealing. weldability of the ufg sample was studied by nd: yag laser welding under different welding conditions. taguchi experimental design was used to optimize the effect of frequency, welding time, laser current and laser pulse duratio...

Porous materials with ligament sizes in the submicrometer to nanometer regime have a high potential for future applications such as catalysts, actuators, or radiation tolerant materials, which require properties like high strength-to-weight ratio, high surface-to-volume ratio, or large interface density as for radiation tolerance. The objective of this work was to manufacture ultra-fine porous ...

We performed molecular dynamics (MD) simulations to investigate the mechanical properties of polycrystalline graphene. By constructing molecular models of ultra-fine-grained graphene structures, we studied the effect of different grain sizes of 1-10 nm on the mechanical response of graphene. We found that the elastic modulus and tensile strength of polycrystalline graphene decrease with decreas...

An ultra-fine-grained AISI 301LN austenitic stainless steel has been achieved by heavy cold rolling, to induce the formation of martensite, and subsequent annealing at 800 C, 900 C, and 1000 C, from 1 to 100 seconds. The microstructural evolution was analyzed using transmission electron microscopy and the yield strength determined by tension testing. Ultra-fine austenite grains, as small as ~0....

Nanostructured (NS) and ultrafine-grained (UFG) materials have high strength and relatively low ductility. Their toughness has not been comprehensively investigated. Here we report the Charpy impact behavior and the corresponding microstructural evolutions in UFG Cu with equi-axed and elongated grains which were prepared by equal channel angular pressing (ECAP) for 2 and 16 passes at room tempe...

At room temperature, the indentation morphologies of crystalline copper with different 13 grain size including nanocrystalline (NC), ultrafine-grained (UFG) and coarse-grained (CG) copper 14 were studied by nanoindentation at the strain rate of 0.04/s without holding time at indentation 15 depth of 2000 nm. As the grain size increasing, the height of the pile-up around the residual 16 indentati...