Atomic picture of elastic deformation in a metallic glass
نویسندگان
چکیده
The tensile behavior of a Ni60Nb40 metallic glass (MG) has been studied by using ab initio density functional theory (DFT) calculation with a large cell containing 1024 atoms (614 Ni and 410 Nb). We provide insight into how a super elastic limit can be achieved in a MG. Spatially inhomogeneous responses of single atoms and also major polyhedra are found to change greatly with increasing external stress when the strain is over 2%, causing the intrinsically viscoelastic behavior. We uncover the origin of the observed super elastic strain limit under tension (including linear and viscoelastic strains) in small-sized MG samples, mainly caused by inhomogeneous distribution of excess volumes in the form of newly formed subatomic cavities.
منابع مشابه
Super elastic strain limit in metallic glass films
On monolithic Ni-Nb metallic glass films, we experimentally revealed 6.6% elastic strain limit by in-situ transmission electron microscopy observations. The origin of high elastic strain limit may link with high free volume in the film, causing the rearrangement of loosely bonded atomic clusters (or atoms) upon elastic deformation. This high elastic limit of metallic glass films will shed light...
متن کاملRevealing anelasticity and structural rearrangements in nanoscale metallic glass films using in situ TEM diffraction
We used a novel diffraction-based method to extract the local, atomic-level elastic strain in nanoscale amorphous TiAl films during in situ transmission electron microscopy deformation, while simultaneously measuring the macroscopic strain. The complementary strain measurements revealed significant anelastic deformation, which was independently confirmed by strain rate experiments. Furthermore,...
متن کاملDeformation in Metallic Glasses Studied by Synchrotron X-Ray Diffraction
High mechanical strength is one of the superior properties of metallic glasses which render them promising as a structural material. However, understanding the process of mechanical deformation in strongly disordered matter, such as metallic glass, is exceedingly difficult because even an effort to describe the structure qualitatively is hampered by the absence of crystalline periodicity. In sp...
متن کاملDeformation of Glass-Forming Metallic Liquids: Configurational Changes and Their Relation to Elastic Softening
5.1 Abstract The change in the configurational enthalpy of metallic-glass-forming liquids induced by mechanical deformation and its effect on elastic softening is assessed. The acoustically measured shear modulus is found to decrease with increasing configurational enthalpy by a dependence similar to one obtained by softening via thermal annealing. This establishes that elastic softening is gov...
متن کاملMetallic glasses: Family traits.
The disordered atomic structure of metallic glasses gives rise to unique mechanical and physical properties such as strength and elasticity, and are being considered for a wide range of applications. However, to understand and ultimately control these properties, it is important to study their disordered structure. Seen on the macroscale, metallic glasses are isotropic and homogeneous. On the m...
متن کامل