The Study Of Directional Solidification

• Main Authors: Guang-Fu He, 何廣福
• Other Authors: Long-Sun Chao
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/75326157620092850206

碩士 === 國立成功大學 === 工程科學系碩博士班 === 93 === 　To control the morphology of solidifying microstructure is difficult in a casting process, in which only the grain size can be easily changed. To perform advanced casting techniques such as directional solidification and the growth of single crystal, a proper casting mechanism is needed to control solidifying microstructures. The fabricating technique of single crystal is based on that of directional solidification. Among these solidification processes, the growth of single crystal is the most difficult one and directional solidification the second. To obtain directional solidification, in this paper, five different kinds of experiment models are designed to investigate the resulting microstructures and their relationships with the axial temperature profiles. In this study, Pb-Sn alloy is used as the testing material and the optical microscope is utilized to observe the solidifying microstructures. The grain number of the lateral cross section is counted and thermal couples are used to measure the temperatures along the axial direction of the cylindrical casting. From the microstructures on the lateral and longitudinal cross sections, the grain number and axial temperature distributions, the relationship among the morphology and size of grain and the solidifying environment is investigated for those five experimental models. From the analysis results, the controlled mechanism of directional solidification can be regulated.