The high undercooling and rapid solidification of Ni-10%Cu-10%Fe-10%Co quaternary alloy were achieved by electromagnetic levitation and glass fluxing techniques. The maximum undercooling of 276 K (0.16TL) was obtained...The high undercooling and rapid solidification of Ni-10%Cu-10%Fe-10%Co quaternary alloy were achieved by electromagnetic levitation and glass fluxing techniques. The maximum undercooling of 276 K (0.16TL) was obtained in the experiments. All the solidified samples are determined to be α-Ni single-phase solid solutions by DSC thermal analysis and X-ray diffraction analysis. The microstructure of the α-Ni solid solution phase transfers from dendrite to equiaxed grain with an increase in undercooling, accompanied by the grain refinement effect. When the undercooling is very large, the solute trapping effect becomes quite significant and the microseg-regation is suppressed. The experimental measure-ment of α-Ni dendrite growth velocity indicates that it increases with undercooling according to the relation, V=8×10?2×?T1.2.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.50121101,50271058 and 50395105)the Doctorate Foundation of Northwestern Polytechnique Universitythe NPU Young Teachers Scientific and Technological Innovation Foundation.
文摘The high undercooling and rapid solidification of Ni-10%Cu-10%Fe-10%Co quaternary alloy were achieved by electromagnetic levitation and glass fluxing techniques. The maximum undercooling of 276 K (0.16TL) was obtained in the experiments. All the solidified samples are determined to be α-Ni single-phase solid solutions by DSC thermal analysis and X-ray diffraction analysis. The microstructure of the α-Ni solid solution phase transfers from dendrite to equiaxed grain with an increase in undercooling, accompanied by the grain refinement effect. When the undercooling is very large, the solute trapping effect becomes quite significant and the microseg-regation is suppressed. The experimental measure-ment of α-Ni dendrite growth velocity indicates that it increases with undercooling according to the relation, V=8×10?2×?T1.2.
