Strengthening by grain refinement via the Hall–Petch mechanism and softening nanograin formation inverse have been subject of argument for decades, particularly ultrafine-grained materials. In this study, relationship is examined magnesium, aluminum, copper, iron produced severe plastic deformation in literature. Magnesium, their alloys follow with a low slope, but an up-break appears when size...

The dependency of uniform corrosion of structural steel on the average grain size (D) should be quantified for design purposes. In the present work, a spectrum of grain sizes was obtained by simple heat treatment routes in st37 structural steel. It was revealed that the corrosion current density (icorr) increased by grain refinement, which was related to the increased density of grain boundarie...

Metals with nanoscale twins have shown ultrahigh strength and excellent ductility, attributed to the role of twin boundaries (TBs) as strong barriers for the motion of lattice dislocations. Though observed in both experiments and simulations, the barrier effect of TBs is rarely studied quantitatively. Here, with atomistic simulations and continuum based anisotropic bicrystal models, we find tha...

In this study, the structural and nanomechanical properties of Cu₂O thin films are investigated by X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM) and nanoindentation techniques. The Cu₂O thin films are deposited on the glass substrates with the various growth temperatures of 150, 250 and 350 °C by using radio frequency magnetron sputtering. The XRD re...

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...

The nanomechanical properties of BiFeO3 (BFO) thin films are subjected to nanoindentation evaluation. BFO thin films are grown on the Pt/Ti/SiO2/Si substrates by using radio frequency magnetron sputtering with various deposition temperatures. The structure was analyzed by X-ray diffraction, and the results confirmed the presence of BFO phases. Atomic force microscopy revealed that the average f...

Thongchai Pratipanawatr MD*, Petch Rawdaree MD**, Thanya Chetthakul MD***, Pongamorn Bunnag MD***, Chardpraorn Ngarmukos MD***, Yupin Benjasuratwong MD****, Rattana Leelawatana MD*****, Natapong Kosachunhanun MD******, Nattachet Plengvidhya MD*******, Chaicharn Deerochanawong MD********, Sompongse Suwanwalaikorn MD*********, Sirinate Krittiyawong MD********** Sirima Mongkolsomlit BSc**********,...

Ultrafine-grained materials display almost no strain hardening, an enhanced rate sensitivity and grain boundary offsets during plastic deformation. It is expected that dislocation climb active in order to enable prompt recovery. The present analysis proposes a deformation mechanism includes these effects follows from the for high temperature sliding. This predicts relationship between rate, flo...