Much interest has been focused on the dendrite growth of undercooled melts in the theoretical field of solidification research. The BCT model was widely accepted to interpret dendrite growth behavior in rapid solidification process. In present case, substantial undercooling ΔT up to 415 K was achieved for Co80Pd20 melt applying molten glass denucleation combined with cyclic superheating. The dendritic morphology of the experimental alloy was investigated by OM and the solute concentration of appointed micro-area was analyzed by EDS. Based on the BCT dendrite growth model, the theoretical calculation of the related parameters of the dendrite growth process included tip radius R, dendrite growth velocity V, solute concentration in liquid at dendrite tip CL* and undercooling contributions were completed. It can be found that the dendritic morphology was only formed in the undercooling ranges of 0-72 K and 95-142 K. With the initial undercooling increasing, V rises steeply due to the increase of the growth driving force, but R displays a complicated variation attributed to the combine effects of thermal/solute diffusion. EDS analysis reveals that the experimental data of CL* is in accordance with the theoretical predication by BCT model. The results confirmed that the dendrite growth in undercooled Co80Pd20 melts can be interpreted successfully by BCT model.
[1] Becker C A, Olmsted D, Asta M, Hoyt J J, Foiles S M. Phys Rev Lett, 2007; 98: 125701
[2] Dragnevski K, Cochrane R F, Mullis A M. Phys Rev Lett, 2002; 89: 215502
[3] Wang H P, Yao W J, Wei B. Appl Phys Lett, 2006; 89: 201905
[4] Laxmanan V. Phys Rev, 1998; 57E: 2004
[5] Bisang U, Bilgram J H. Phys Rev, 1996; 54E: 5309
[6] Zang D Y, Wang H P, Wei B B. Acta Phys Sin, 2007; 56: 4804
(臧渡洋, 王海鹏, 魏炳波. 物理学报, 2007; 56: 4804)
[7] Yao W J, Wei B B. Sci China, 2004; 34E: 1
(姚文静, 魏炳波. 中国科学, 2004; 34E: 1)
[8] Lipton J, Kurz W, Trivedi R. Acta Metall, 1987; 35: 957
[9] Boettinger W J, Coriell S R, Trivedi R. In: Mehrabian R, Parrish P A eds., Proc 4th Conf on Rapid Solidification Processing: Principles and Technologies. Baton Rouge, LA: Claitors Publishing Division, 1987: 13
[10] Galenko P K, Danilov D A. Phys Lett, 1997; 235A: 271
[11] Wang H F, Liu F, Yang G C, Zhou Y H. Acta Mater, 2010; 58: 5402
[12] Herlach D M. Mater Sci Eng, 1994; R12: 177
[13] Holland–Moritz D, Herlach D M, Spaepen F. Superlattice Microst, 2007; 41: 196
[14] Wilde G, G¨orler G P, Willnecker R. Appl Phys Lett, 1996; 69: 2995
[15] Wilde G, G¨orler G P, Willnecker R. Appl Phys Lett, 1996; 69: 2953
[16] Jacobs G, Egry I. Phys Rev, 1999; 59B: 3961
[17] Zhou S Y, Hu R, Li J S, Chang H, Kou H C, Zhou L. Mater Sci Eng, 2010; A528: 973
[18] Zhou S Y, Hu R, Jiang L, Li J S, Kou H C, Chang H, Zhou L. J Mater Sci (submitted)
[19] Li J F, Yang G C, Zhou Y H. Acta Metall Sin, 1998; 34: 113
(李金富, 杨根仓, 周尧和. 金属学报, 1998; 34: 113)
[20] Chen Y Z, Yang G C, Liu F, Liu N, Xie H, Zhou Y H. Acta Metall Sin, 2006; 42: 703
(陈豫增, 杨根仓, 刘峰, 刘宁, 谢 辉, 周尧和. 金属学报, 2006; 42: 703)
[21] Liu N, Yang G C, Liu F, Chen Y Z, Yang C L, Zhou Y H. Acta Metall Sin, 2007; 43: 449
(刘宁, 杨根仓, 刘峰, 陈豫增, 杨长林, 周尧和. 金属学报, 2007; 43: 449)
[22] Liu F, Guo X F, Yang G C. Mater Res Bull, 2001; 36: 181
[23] Lu S Y, Li J F, Zhou Y H. J Crst Growth, 2007; 309: 103
[24] Zhou J, Xie F Q, Wu X Q, Zhang J. Acta Metall Sin, 2009; 45: 385
(周俊, 谢发勤, 吴向清, 张军. 金属学报, 2009; 45: 385)
[25] Langer J S, Muller–Krumbhaar H. Acta Metall, 1978; 26: 1681
[26] Volkmann T, Wilde G, Willnecker R, Herlach D M. J Appl Phys, 1998; 83: 3028
[27] Galenko P K, Funke O, Wang J, Herlach D M. Mater Sci Eng, 2004; A375–377: 488
[28] Funke O, Phanikumar G, Galenko P K, Chernova L, Reutzel S, Kolbe M, Herlach D M. J Crst Growth, 2006; 297: 211
[29] Aziz M J. J Appl Phys, 1982; 53: 1158
[30] Li J F, Lu Y L, Yang G C, Zhou Y H. Acta Metall Sin, 1998; 34: 586
(李金富, 吕衣礼, 杨根仓, 周尧和. 金属学报, 1998; 34: 586)
