Solidification characteristics of near rapid and supercooling directional solidification

Comparing the solidification characteristics of supercooling directional solidification(SDS) with constrained directional solidification(D. S. ) and considering the inheritance of supercooled melt, the supercooling directional solidification technique with the combination of melt supercooing and traditional directional solidification was proposed. An exploring study on SDS techniques was also conducted by using appropriate selfmade facilities and the deep supercooling of Cu-5. O % Ni alloy and its directional solidification were implemented. The experimental results show that: 1 ) the solidification microstructure produced by SDS are nearly the same as that by LMC technique, its primary arm spacing is around 30 Um in average and the secondary sidebranch is considerably degenerated; 2) the primary arm trunk of microstructure appears straight and fine, and the average deviation of crystal growth orientation from the axial line is about 5. 8; 3) a mathematical model describing the relationship between melt supercooling by SDS and the solidification rate, namely T-T model,was established, by which the microstructure evolution in SDS can be explained.

Comparing the solidification characteristics of supercooling directional solidification (SDS) with constrained directional solidification (D. S.) and considering the inheritance of supercooled melt, the supercooling directional solidification technique with the combination of melt supercooling and traditional directional solidification was proposed. An exploring study on SDS techniques was also conducted by using appropriate self-made facilities and the deep supercooling of Cu-5.0 % Ni alloy and its directional solidification were implemented. The experimental results show that: 1) the solidification microstructure produced by SDS are nearly the same as that by LMC technique, its primary arm spacing is around 30 mu m in average and the secondary sidebranch is considerably degenerated; 2) the primary arm trunk of microstructure appears straight and fine, and the average deviation of crystal growth orientation from the axial line is about 5.8 degrees; 3) a mathematical model describing the relationship between melt supercooling by SDS and the solidification rare, namely T-T model, was established, by which the microstructure evolution in SDS can be explained.