Numerical calculation of flow field inside TiAl melt during rectangular
cold crucible directional solidification
cold crucible directional solidification
(School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China)
Abstract: Numerical investigations on the flow field in Ti−Al melt during rectangular cold crucible directional solidification were carried out. Combined with the experimental results, 3-D finite element models for calculating flow field inside melting pool were established, the characteristics of the flow under different power parameters were further studied. Numerical calculation results show that there is a complex circular flow in the melt, a rapid horizontal flow exists on the solid/liquid interface and those flows confluence in the center of the melting pool. The flow velocity v increases with the increase of current intensity, but the flow patterns remain unchanged. When the current is 1000 A, the vmax reaches 4 mm/s and the flow on the interface achieves 3 mm/s. Flow patterns are quite different when the frequency changes from 10 kHz to 100 kHz, the mechanism of the frequency influence on the flow pattern is analyzed, and there is an optimum frequency for cold crucible directional solidification.
Key words: flow field; numerical calculation; TiAl alloys; cold crucible; directional solidification