Industrial pure iron samples were austenitized and quenched (6°C/s cooling to room temperature) under hydrostatic pressure of 3–5 GPa. The morphology, phase transformation strengthening mechanism high-pressure martensite are analyzed by the method SEM, XRD, EBSD, TEM. Lath with hierarchical packet-block-lath structure is induced in industrial high pressure, which keeps Kurdjumov-Sachs (K-S) ori...

Mechanical properties in tension of cobalt have been studied a wide range grain size d using thickness t samples from 125 to 700 ?m. The Hall and Petch (HP) relationship indicates that the yield stress strongly varies for t/d below critical value around 14, highlighting existence multicrystalline regime. behavior becomes almost single crystalline when is lower than 2.5, with very small HP slope...

The effects of grain size and boundary stability on the mechanical fatigue properties nanocrystalline nickel thin films were examined. We found that tended to decrease with amount sodium allylsulfonate, solution side was larger than substrate side. dependence 0.2% proof strength, tensile limit could be expressed by Hall–Petch equation. strength annealed film are lower those as-deposited film, w...

Stress-relaxation experiments were performed on nanotwinned Cu to characterize the twin size-dependence of the activation volume and mobile dislocation density. We find that the variation of activation volume as a function of twin lamellae thickness can be captured well by a Hall–Petch-type relation. This structure size-dependence is interpreted to arise from a transition of the rate-controllin...

The growth in investment on the effect of size in nanoscience and nanotechnology has been astounding. Of the $12.4B spent in 2006 worldwide Nanotechnology research funding [1], at least 50 % was spent on the effect of size for the development of nanomaterials and devices. The focus of nanoscience is to understand the influence of size on the material properties, while nanotechnology focuses on ...

The mechanical properties and microstructural developments of 321 stainless steel during thermomechanical process were investigated. The repetitive cold rolling and subsequent annealing were conducted to achieve nanocrystalline structure in an AISI 321 stainless steel. Heavily cold rolling at −20°C was conducted to form martensite in metastable austenitic steel. The process was followed by anne...