Effect of sample diameter on primary and secondary dendrite arm spacings during directional solidification of Pb-26wt.%Bi hypo-peritectic alloy  

作　　者：HU Xiaowu YAN Hong CHEN Wenjing LI Shuangming FU Hengzhi 

机构地区：[1]School of Mechanical-Electrical Engineering, Nanchang University, Nanchang 330031, China [2]Department of Applied Physics, Northwestern P olytechnical University, Xi＇an 710072, China [3]State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi＇an 710072, China

出　　处：《Rare Metals》2011年第4期424-431,共8页稀有金属（英文版）

基　　金：supported by the China Postdoctoral Science Foundation (No. 20110491492);National Natural Science Foundation of China (No. 50765005);the Innovative Group of Science and Technology of College of Jiangxi Province,China (No. 00008713)

摘　　要：The microstructure scales of dendrites, such as primary and secondary dendrite arm spacings, control the segregation profiles and the formation of secondary phases within interdendritic regions, which determine the properties of solidified structures. Investigations on primary and secondary dendrite arm spacings of primary a-phase during directionally solidified Pb-26wt%Bi hypo-peritectic alloy were carried out in this research, and systematic studies were conducted using cylindrical samples with different diameters （Ф = 1.8 and 7.0 mm） in order to analyze the effects of sample diameter on the primary and secondary dendrite arm spacings. In this work, the dependence of dendrite arm spacings on growth velocity was established. In addition, the experimental data concerning the primary and secondary dendrite ann spacings were compared with the main predictive dendritic models from the literatures. A comparison between experimental results for dendrite arm spacings of the 1.8-mm-diameter sample and 7.0-ram-diameter sample was also conducted.The microstructure scales of dendrites, such as primary and secondary dendrite arm spacings, control the segregation profiles and the formation of secondary phases within interdendritic regions, which determine the properties of solidified structures. Investigations on primary and secondary dendrite arm spacings of primary a-phase during directionally solidified Pb-26wt%Bi hypo-peritectic alloy were carried out in this research, and systematic studies were conducted using cylindrical samples with different diameters （Ф = 1.8 and 7.0 mm） in order to analyze the effects of sample diameter on the primary and secondary dendrite arm spacings. In this work, the dependence of dendrite arm spacings on growth velocity was established. In addition, the experimental data concerning the primary and secondary dendrite ann spacings were compared with the main predictive dendritic models from the literatures. A comparison between experimental results for dendrite arm spacings of the 1.8-mm-diameter sample and 7.0-ram-diameter sample was also conducted.

关 键 词：lead bismuth alloys dendrite arm spacing directional solidification DENDRITES 

分 类 号：TG146.21[一般工业技术—材料科学与工程] TQ136.11[金属学及工艺—金属材料]