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...

The response to cyclic deformation has been studied for Cu/Cu multilayer material consisting of columns of closely spaced, parallel nanotwins. The fatigue life under stress-controlled cycling is greatly improved over that of coarse-grained Cu. Nanotwinning provides significant strengthening, which is unchanged by fatigue or severe compression. Observations by focused ion beam microscopy showed ...

By adding nanotwins to Cu, the surface electromigration (EM) slows down. The atomic mobility of the surface step-edges is retarded by the triple points where a twin meets a free surface to form a zigzag-type surface. We observed that EM can alter the zigzag surface structure to optimize the reduction of EM, according to Le Chatelier's principle. Statistically, the optimal alternation is to chan...

Material performance in extreme radiation environments is central to the design of future nuclear reactors. Radiation induces significant damage in the form of dislocation loops and voids in irradiated materials, and continuous radiation often leads to void growth and subsequent void swelling in metals with low stacking fault energy. Here we show that by using in situ heavy ion irradiation in a...

Reversible hydrogen uptake and the metal/dielectric transition make Mg/MgH2 system a prime candidate for solid-state storage dynamic plasmonics. However, high dehydrogenation temperatures slow hamper broad applicability. One promising strategy to improve is formation of metastable γ-MgH2. A nanoparticle (NP) design, where γ-MgH2 forms intrinsically during hydrogenation presented mechanism based...

Nanotwin formation is observed during laser powder bed fusion (LPBF) of austenitic stainless steels fabricated with various process parameters. Transmission electron microscopy was employed to reveal the nature such twins, which are formed due high strain rapid solidification inherent LPBF. Dynamic recrystallization (DRX) also activated LPBF, and induced by deformation nanotwins. A thermostatis...