In this study, mechanochemcical process(MCP) is applied to synthesize ultrafine TaC powders. In this research, nano powder composite TaC-TaB2 was produced using mixtures of tantalum carbide and boron carbide as raw materials via mechanochemical process. The phase formation characterization during process was utilized by X-ray diffractometry (XRD). The morphology of synthesized powder was studie...

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...

The first molecular dynamics (MD) study was conducted to explore mechanical-failure response of ultrafine grained single-layer boron-nitride films. We used MD simulations to construct relatively large molecular models of polycrystalline structures with random grain configurations. By applying uniaxial tensile loading, we then studied the grain size effect on the mechanical response of polycryst...

The titanium powder embedded with 2.5 vol% TiB was in-situ fabricated by gas atomization and applied for direct laser deposited (DLD) matrix composites. Consistent the network distributed boron-rich zone in composite powder, a three-dimensional (3D) ultrafine structure, consisting of nano-TiB whiskers (TiBw), characterized throughout as-fabricated (DLDed TiB–Ti). Both dendritic equiaxed network...

Bulk ultrafine grained (UFG)/nanocrystal metals possess exceptional strength but normally poor ductility and thermal stability, which hinder their practical applications especially in high-temperature environments. Through microalloying strategy that enables the control of grains and precipitations in nanostructured regime, here we design and successfully produce a highly microstructure-stable ...

The knowledge of the fracture of bulk metallic materials developed in the last 50 years is mostly based on materials having grain sizes, d, in the range of some micrometres up to several hundred micrometres regarding the possibilities of classical metallurgical methods. Nowadays, novel techniques provide access to much smaller grain sizes, where severe plastic deformation (SPD) is one of the mo...

Nanoindentation morphologies of crystalline copper have been probed at the grain scale. Experimental tests have been conducted on nanocrystalline (NC), ultrafine-grained (UFG), and coarse-grained (CG) copper samples with a new Berkvoich indenter at the strain rate of 0.04/s without holding time at an indentation depth of 2000 nm at room temperature. As the grain size increases, the height of th...

Al–Mg alloy powder was cryomilled to achieve a nanocrystalline (NC) structure having an average grain size of 50 nm with high thermal stability, and then consolidated by quasi-isostatic forging. The consolidation resulted in a bulk material with ultrafine grains of about 250 nm, and the material exhibited enhanced strength compared to conventionally processed Al–Mg alloy. The hardness of as-cry...

Two different aspects of the thermal stability of grains were studied – (i) thermal stability of grain structure evolution during friction stir processing (FSP), and (ii) thermal stability of grains after FSP. It was concluded that Al3(Sc,Zr) dispersoids are effective in limiting grain growth to ultrafine grained regime (UFG) by stabilizing the microstructure during FSP. The presence of these d...