For the first time, tribological behaviour of 316 L stainless steel (316 SS) additively manufactured via laser powder bed fusion (L-PBF) with ultrafine- and nano-grains obtained from high-pressure torsion (HPT) processing has been investigated. The pin-on-disk dry sliding wear test results demonstrate enhancement performance after HPT processing, as indicated by consistently lower coefficient f...

Abstract The strength of polycrystal increases as the grain diameter l decreases, i.e. Hall–Petch behaviour. This trend reverses at about 3 < 15 nm, inverse-Hall–Petch How size affects material’s nm (~12 particles) remains unclear. Here our simulations use mixtures soft and hard particles so that compression can continuously reduce to merely a few particles, resulting in ultrafine-grained so...

Abstract In the current study, effect of equal channel angular pressing parameters such as die route type and angle were studied. Billets pure magnesium (Mg) processed successfully through up to 2-passes different routes, A, Bc, C, using dies with internal angles 90° 120° at 225°C. The crystallographic texture microstructural evolution investigated electron back-scatter diffraction. Vickers mic...

Abstract The rapid development of high-speed rail requires copper contact wire that simultaneously possesses excellent electrical conductivity, thermal stability and mechanical properties. Unfortunately, these are generally mutually exclusive Here, we demonstrate directional optimization microstructure overcome the strength-conductivity tradeoff in wire. We use rotary swaging to prepare with a ...

A review on the microstructural evolution in magnesium alloys during severe plastic deformation waspresented. The challenges deserved to achieve ultrafine/ nanostructured magnesium were discussed.The characteristics of the processed materials are influenced by three main factors, including i)difficult processing at low temperatures, ii) high temperature processing and the occurrence ofdynamic r...

accumulative roll-bonding (arb) is a severe plastic deformation process that is using rolling to produce ultrafine grains in coarse grained metallic materials. in this study, arb has been applied on 70/30 brass up to 6 cycles at ambient temperature and non-lubricated conditions to apply a true strain up to 4.8 von mises strain. microstructures of arbed brass samples were characterized by scanni...

Recently it was speculated that ultrafine particles may translocate from deposition sites in the lungs to systemic circulation. This could lead to accumulation and potentially adverse reactions in critical organs such as liver, heart, and even brain, consistent with the hypothesis that ultrafine insoluble particles may play a role in the onset of cardiovascular diseases, as growing evidence fro...

Recently, toxicological and epidemiological studies on health effects related to particle exposure suggest that 'ultrafine particles' (particles with an aerodynamic diameter of <100 nm) may cause severe health effects after inhalation. Although the toxicological mechanisms for these effects have not yet been explained, it is apparent that measuring exposures against mass alone is not sufficient...

Air pollution is associated with cardiovascular mortality. Inhaled ultrafine particles translocate into the blood. Amine-polystyrene ultrafine particles significantly enhance experimental thrombus formation in a damaged hamster vessel and shorten the closure time in the Platelet Function Analyser. Diesel exhaust particles are thrombogenic within one hour of intratracheal instillation and shorte...

The main objective of this study was to develop parsimonious empirical models for predicting the mass and number concentrations of ultrafine particulate (UFP, aerodynamic diameter < 0.1 or 0.18 microm) in the atmospheric environment. We found strong correlations existed between the mass/number concentration of UFP and the mass concentration of PM(2.5) (aerodynamic diameter < 2.5 microm) by fitt...