Phase separated metallic glasses were prepared in the Gd-Hf-Co-Al system by rapid quenching of the melt. Due to the strong positive enthalpy of mixing between the main constituent elements Gd and Hf (ΔHGd-Hf = +11 kJ/mol) a heterogeneous microstructure is formed consisting of two amorphous phases, which are Gd-enriched and Hf-enriched, respectively. The size of the phase separated regions varies from 0.1 μm to 5 μm, depending on alloy composition and cooling rate. Different types of microstructure, such as an interconnected structure or a droplet structure were obtained as a function of cooling rate. The microstructure of the phase separated metallic glasses is determined not only by their composition, the critical temperature, and the shape of the miscibility gap, but also by the viscosity and diffusivity of the melt.
Bibliographical noteFunding Information:
Financial support of the Deutsche Forschungsgemeinschaft DFG (Ma1531/10) and the Global Research Laboratory (GRL) Program of Korea Ministry of Education, Science and Technology are gratefully acknowledged.
All Science Journal Classification (ASJC) codes
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry