In this study, bulk ultrafine-grained and micro-crystalline cobalt was prepared using a combination of high-energy ball milling and subsequent spark plasma sintering. The average grain sizes of the ultrafine-grained and micro-crystalline materials were 200 nm and 1 μm, respectively. Mechanical properties such as the compressive yield strength, the ultimate compressive strength, the maximum comp...

In the automotive industry, mechanical grinding is employed at finishing line rectification to remove defects left over from upstream, which may also result in microstructure modification within near-surface region of work piece and, consequently, affects its corrosion performance. The present investigates influence on and behaviour Al–Si–Mg (A356) alloy castings order advance understanding pot...

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...

We conducted a series of experiments with ultrafine particles (approximately 20 nm) and larger particles (less than 200 nm) of "nuisance" dusts to evaluate the involvement of alveolar macrophages (AM) in particle-induced lung injury and particle translocation in rats. After intratracheal instillation of both ultrafine particles and larger particles of TiO2, we found a highly increased interstit...

Respirable ambient particles [particulate matter <10 μm (PM10)] are associated with both acute and chronic adverse health effects including chronic airflow obstruction. PM10 can induce expression of inflammatory and fibrogenic mediators, but there is controversy about the types and/or sizes of particles involved and, in particular, whether ultrafine particles are the major toxic agents. To exam...

This study investigated water-soluble ions in the sized particles (particularly nano (PM(0.01-0.056))/ultrafine (PM(0.01-0.1))) collected using MOUDI and Nano-MOUDI samplers near a busy road site and at a rural site. The analytical results demonstrate that nano and coarse particles exhibited the highest (16.3%) and lowest (8.37%) nitrate mass ratios, respectively. The mass ratio of NO(3)(-) was...

The aim of this study is to assess the levels of airborne ultrafine particles emitted in welding processes (tungsten inert gas [TIG], metal active gas [MAG] of carbon steel, and friction stir welding [FSW] of aluminum) in terms of deposited area in pulmonary alveolar tract using a nanoparticle surface area monitor (NSAM) analyzer. The obtained results showed the dependence of process parameters...

Microstructure, texture and tensile properties of ultrafine/nano grained 1 magnesium alloy processed by accumulative back extrusion 2 3 S.M. Fatemi, A. Zarei-Hanzaki, J.M. Cabrera 4 5 a School of Mechanical Engineering, Shahid Rajaee Teacher Training University, 136-16785, Tehran, Iran 6 b Department of Metallurgical & Materials Engineering, University of Tehran, 515-14395, Tehran, Iran 7 c Dep...

Materials with ultrafine grain sizes are attractive for use in micro-forming operations. High-pressure torsion (HPT) is an effective technique that allows disc materials subjected to torsional deformation to generate microstructures with significant grain refinement. Generally, ultrafine-grained materials exhibit high strength but their ductility is limited because they have both a low rate of ...