the formation of nano/ultrafine grained ferrite in low carbon steels containing different amounts of niobiumwas investigated using thermomechanical treatment which consisted of annealing of 85% cold rolled martensite with different parameters. the specimens were characterized by optical and scanning electron microscopy and vickers hardness test. a lamellar dislocation cell structure was formed ...

There are serious questions about the grain structure of metals after laser melting and the ways that it can be controlled. In this regard, the current paper explains the grain structure of metals after laser melting using a new model based on combination of 3D finite element (FE) and cellular automaton (CA) models validated by experimental observation. Competitive grain growth, relation betwee...

The recent results of the application of diffraction techniques to study the atomic structure of grain boundaries are reviewed. The outcome of the first determination of a grain boundary structure using diffraction information alone is examined. The influence of a particular metal on the grain boundary structure is examined. The variation of grain boundary structural width with parameters such ...

The grain size refinement of AISI 422 martensitic stainless steel in the temperature range of 950-1150 ºC was investigated by hot deformation tests. The deformed specimens were held at deformation temperature with delay times of 5 to 300s after achieving a strain of 0.3. The austenite grains exhibit a considerable growth at temperature higher than 1050˚C, while the grain coarsening is negligibl...

In order to investigate the effects of the grain size distribution and the micro-structure of soils on the mechanical characteristics, some static triaxial compression tests were carried out, and then the relationship of stress-strain and the strength behavior of silty sand were compared among undisturbed samples with different grain size distribution, undisturbed and remolded samples with the ...

We have identified a new defect at the intersection between grain boundaries and surfaces in Au using atomic resolution transmission electron microscopy. At the junction line of 90 degrees <110> tilt grain boundaries of (110)-(001) orientation with the free surface, a small segment of the grain boundary, about 1 nm in length, dissociates into a triangular region with a chevronlike stacking diso...

A new version of the stream cipher Grain-128 is proposed. The new version, Grain-128a, is strengthened against all known attacks and observations on the original Grain-128, and has built-in support for authentication. The changes are modest, keeping the basic structure of Grain-128. This gives a high confidence in Grain-128a and allows for easy updating of existing implementations.

A new version of the stream cipher Grain-128 is proposed. The new version, Grain-128a, is strengthened against all known attacks and observations on the original Grain-128, and has built-in support for optional authentication. The changes are modest, keeping the basic structure of Grain-128. This gives a high confidence in Grain-128a and allows for easy updating of existing implementations.

The extrinsic grain boundary dislocations (EGBD's) in copper have been studied by transmission electron microscopy. It was shown that some EGBD's remain on grain boundaries after recrystallization and annealing at 0.6 T,, but not on those annealed at 0.8 T,. For several grain boundaries the crystallography of the defects was examined in detail and the dynamic theory of diffraction was used for ...