The main aim of the current project has been to produce a batch of bulk billets with ultrafine-grained (UFG) microstructure and enhanced strength made of two refractory metals such as tungsten and tantalum. To process bulk W billets with UFG structure having a long-length size more than 100 mm we have developed and successfully used a new approach based on a combination of equal angular pressin...

The fabrication of the micro-channel array through micro-embossing on an ultrafine-grained (UFG) LZ91 Mg-Li alloy was investigated in this paper. Micro-embossing tests indicated that the depth of the channels increase with increasing temperatures. Micro-array channels with widths ranging from 50 μm to 200 μm were performed with an applied force of 2 kN at 423 K, following by a dwell time of 60 ...

To provide insight into the relationships between precipitation phenomena, grain size and mechanical behavior in a complex precipitation-strengthened alloy system, Al 7075 alloy, a commonly used aluminum alloy, was selected as a model system in the present study. Ultrafine-grained (UFG) bulk materials were fabricated through cryomilling, degassing, hot isostatic pressing and extrusion, followed...

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...

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...

We describe here for the first time the low temperature superplasticity of nanostructured low carbon steel (microalloyed with V, N, Mn, Al, Si, and Ni). Low carbon nanograined/ultrafine-grained (NG/UFG) bulk steel was processed using a combination of cold-rolling and annealing of martensite. The complex microstructure of NG/UFG ferrite and 50-80 nm cementite exhibited high thermal stability at ...

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...

In the present study, the effect of grain size on the austenite stability was studied by nanoindentation tests in a 304L stainless steel. Thermomechanical processing based on cold rolling and annealing was used to produce two different types of austenite: ultrafine grained (UFG) austenite with the average grain size of 0.65 μm and coarse grained (CG) austenite with the average grain size of 12 ...

In the present work, new possibilities of the X-ray diffraction for investigations of the 17 phase composition, size, shape and volume fraction of particles in ultrafine-grained (UFG) 18 martensitic steel and the Cu-Cr-Zr alloy have been demonstrated. For the first time, the method of 19 X-ray diffraction in the transmission mode was used to identify particles with a volume fraction of 20 less ...

The processing of metals through the application of severe plastic deformation (SPD) techniques provides the potential for achieving exceptional grain refinement leading to ultrafine-grained (UFG) materials in bulk solids. These materials generally exhibit high strength but very limited ductility at room temperature (RT) leading to the so-called paradox of strength and ductility. The recent dev...