Abnormal grain growth can occur in polycrystalline materials with only a fraction of grains growing drastically to consume other grains. Here we report abnormal ultrafine grained metal rarely explored high-cycle loading regime at ambient temperature. is observed electroplated Ni microbeams average initial sizes less than 640 nm under large number cycles (up 109) low strain amplitudes (< 0.3%). ...

Abstract Copper rods with ultrafine-grained microstructure, obtained by multi-turn ECAP processing, were subjected to Direct Drive Rotary Friction Welding using various processing parameters, such as rotational speed and pressure, which resulted in different energy heat input. Even though friction welding is a high process, proper selection of parameters it was possible maintain grain size at a...

We describe here for the first time the low temperature superplasticity of nanostructured low carbon steel (microalloyed with V, N, Mn, Al, Si, and Ni). Low carbon nanograined/ultrafine-grained (NG/UFG) bulk steel was processed using a combination of cold-rolling and annealing of martensite. The complex microstructure of NG/UFG ferrite and 50-80 nm cementite exhibited high thermal stability at ...

The paper presents the evaluation of the mechanical and fatigue properties of an ultrafine-grained (UFG) Al 6061 alloy processed by high-pressure torsion (HPT) at room temperature (RT). A comparison is made between the UFG state and the coarse-grained (CG) one subjected to the conventional aging treatment Т6. It is shown that HPT processing leads to the formation of the UFG microstructure with ...

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...