Microstructure and fractal characteristics of the solid-liquid interface forming during directional solidification of Inconel 718  

作　　者：WANG Ling DONG Jian-xin LIU Lin ZHANG Mai-cang 

机构地区：[1]High Temperature Materials Research Laboratories, University of Science and Technology Beijing, Beijing 100083, China [2]School of Materials, Hebei University of Science and Technology, Shijiazhuang 050054, China [3]National Key Laboratory of SolidificationTechnology, Northwestern Polytechnical University, Xi＇an 710072, China

出　　处：《China Foundry》2007年第3期182-185,共4页中国铸造（英文版）

基　　金：This work was financially supported by the National Natural Science Foundation of China (No.50371006).

摘　　要：The solidification microstructure and fractal characteristics of the solid-liquid interfaces of Inconel 718,under different cooling rates during directional solidification,were investigated by using SEM. Results showed that 5 μm/s was the cellular-dendrite transient rate. The prime dendrite arm spacing (PDAS) was measured by Image Tool and it decreased with the cooling rate increased. The fractal dimension of the interfaces was calculated and it changes from 1.204310 to 1.517265 with the withdrawal rate ranging from 10 to 100 μm/s. The physical significance of the fractal dimension was analyzed by using fractal theory. It was found that the fractal dimension of the dendrites can be used to describe the solidification microstructure and parameters at low cooling rate,but both the fractal dimension and the dendrite arm spacing are needed in order to integrally describe the evaluation of the solidification microstructure completely.The solidification microstructure and fractal characteristics of the solid-liquid interfaces of Inconel 718, under different cooling rates during directional solidification, were investigated by using SEM. Results showed that 5 μm/s was the cellular-dendrite transient rate. The prime dendrite arm spacing （PDAS） was measured by Image Tool and it decreased with the cooling rate increased. The fractal dimension of the interfaces was calculated and it changes from 1.204310 to 1.517265 with the withdrawal rate ranging from 10 to 100μm/s. The physical significance of the fractal dimension was analyzed by using fractal theory. It was found that the fractal dimension of the dendrites can be used to describe the solidification microstructure and parameters at low cooling rate, but both the fractal dimension and the dendrite arm spacing are needed in order to integrally describe the evaluation of the solidification microstructure completely.

关 键 词：Inconel 718 cooling rate MICROSTRUCTURE fractal dimension solid-liquid interface 

分 类 号：TG132.32[一般工业技术—材料科学与工程]