Nanocrystalline metals are polycrystalline metals with grain sizes in the nanometer range. They have attracted significant interest in recent years due to their unique mechanical and electrical properties. The main objective of this thesis is to develop continuum-scale descriptions of nanoscale deformation and failure mechanisms in nanocrystalline metals. The research has focused on three speci...

A number of recent studies have investigated deformation behavior CoCrFeMnNi (Cantor) alloy at elevated temperatures by using plastic to relatively small strains such as tensile testing. Therefore, little has been known about the this typical FCC high-entropy (HEA) in case that material is subjected ultra-high various temperatures. In present study, equi-atomic HEA was successfully deformed ove...

The microstructure and mechanical properties of Zr48Cu48 - x Al4M x (M ≡ Fe or Co, x = 0, 0.5, 1 at.%) metallic glass (MG) composites are highly dependent on the amount of Fe or Co added as microalloying elements in the parent Zr48Cu48Al4 material. Addition of Fe and Co promotes the transformation from austenite to martensite during the course of nanoindentation or compression experiments, resu...

The mechanisms of deformation under a nanoindentation in tantalum, chosen as a model body-centered cubic (bcc) metal, are identified and quantified. Molecular dynamics (MD) simulations and indentation experiments are conducted for [100], [110] and [111] normals to surface orientations. The simulated plastic deformation proceeds by the formation of nanotwins, which rapidly evolve into shear disl...