We report on molecular-dynamics (MD) simulations of tensile loading of nano-crystalline Al modeled by an embedded-atom method (EAM) potential. Usage of two different sample preparation methods of the nano-crystalline material allows us to compare mechanical properties for different sample qualities. A Voronoi-constructed polycrystal exhibits nearly no pores and has different mechanical properti...

High temperature nanoindentation experiments are conducted to assess the activation enthalpy for deformation of nanocrystalline Ni-W alloys, for grain sizes between 3 and 80 nm. Thermal softening becomes less pronounced at finer grain sizes, and the activation enthalpy has an apparent inflection at a grain size near ~10-20 nm, in the vicinity the Hall-Petch breakdown. This inflection is related...

In the last three decades, several severe plastic deformation (SPD) procedures have been developed and applied in materials science to create bulk, ultrafine-grained (UFG) structures. As a consequence of SPD, not only submicron even nanometer grain sizes can be obtained, but also new boundaries with non-equilibrium structures material may formed. Therefore, both strength ductility UFG change si...

The tribological behavior of dual-phase steels have been studied at the macroscopic scale taking macrohardness as main material property to control friction and wear. However, contribution varying properties phase microscopic are yet be fully understood. In this study, microstructures with various grain sizes martensite volume fraction generated. Microhardness ferrite measured by nanoindentatio...

Welding is an essential fabrication step during the construction of pipelines using high-strength low-alloy steels. The base metal experiences a rapid thermal excursion in heat-affected zone, resulting modification microstructure and mechanical properties. In particular, coarse-grain zone closest to weld pool significance for integrity pipelines. present work, hardness were quantified from labo...

The mechanical strengths of nano-scale individual crystal or nanopolycrystalline metals, and other dimensionally-related materials are increased by an order of magnitude or more as compared to those values measured at conventional crystal or polycrystal grain dimensions. An explanation for the result is attributed to the constraint provided at the surface of the crystals or, more importantly, a...