Origin of embrittlement in metallic glasses

Origin of embrittlement in metallic glasses.

Owing to their glassy nature, metallic glasses demonstrate a toughness that is extremely sensitive to the frozen-in configurational state. This sensitivity gives rise to "annealing embrittlement," which is often severe and in many respects limits the technological advancement of these materials. Here, equilibrium configurations (i.e., "inherent states") of a metallic glass are established aroun...

Structural relaxation kinetics defines embrittlement in metallic glasses

Article history: Received 5 December 2017 Received in revised form 22 January 2018 Accepted 23 January 2018 Available online xxxx Structural relaxation during isothermal annealing, quantified by enthalpy recovery of Zr44Ti11Cu10Ni10Be25 towards its metastable equilibrium and correlation to embrittlement, quantified through fracture toughness, KQ, is studied. Enthalpy relaxation over time obeys ...

Modeling failure of metallic glasses due to hydrogen embrittlement in the absence of external loads

A model is developed to describe the expansion of high-pressure hydrogen bubbles and propagation of cracks between them in the absence of external loads. The focus is on cracks that form during electrochemical hydrogen charging of amorphous Fe80B11Si9 ribbons. A coupled diffusion/fracture mechanics approach is developed, allowing determination of the time to failure. Finite element analyses are...

On the correlation between microscopic structural heterogeneity and embrittlement behavior in metallic glasses

In order to establish a relationship between microstructure and mechanical properties, we systematically annealed a Zr-based bulk metallic glass (BMG) at 100 ~ 300 °C and measured their mechanical and thermal properties. The as-cast BMG exhibits some ductility, while the increase of annealing temperature and time leads to the transition to a brittle behavior that can reach nearly-zero fracture ...

Superconductivity in Metallic Glasses