Simulation of critical cooling rate and process conditions for metallic glasses in vertical type twin-roll casting
(1. Graduate School of Saitama Institute of Technology, Fusaiji 1690, Fukaya, Saitama 369-0293, Japan;
2. Department of Material Science and Engineering, Saitama Institute of Technology, Fusaiji 1690, Fukaya, Saitama 369-0293, Japan;
3. School of Materials and Metallurgy, University of Science and Technology Liaoning, Anshan 114051, China)
Abstract: Critical cooling rates for producing metallic glasses were evaluated based on a calculated continuous cooling transformation (CCT) diagram. Temperature distributions of the melt in molten pool in the vertical type twin-roll casting (VTRC) process of metallic glasses were simulated, and cooling rates under different casting conditions were calculated with the simulated results. By comparing the results obtained by CCT diagrams and simulation, the possibility of producing metallic glasses by the VTRC method and influences of casting conditions on cooling rate were discussed. The results reveal that cooling rate with 3 or 4 orders of magnitude by the VTRC process can be attained in producing Mg-based metallic glasses, which is faster than the critical cooling rate calculated by the CCT diagram. One side pouring mode can improve the temperature distributions of casting pool. VTRC process has a good ability in continuous casting metallic glassy thin strips.
Key words: metallic glass; critical cooling rate; twin-roll casting; simulation