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SIMULATION OF GROWTH KINETICS OF PRO-EUTECTOID FERRITE USING MIXED CONTROL MODEL WITH CONSIDERATION OF DISLOCATION INTERACTION |
Huidong WU,Chi ZHANG,Wenbo LIU,Zhigang YANG( ) |
Key Laboratory of Advanced Materials of Ministry of Education, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 |
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Cite this article:
Huidong WU,Chi ZHANG,Wenbo LIU,Zhigang YANG. SIMULATION OF GROWTH KINETICS OF PRO-EUTECTOID FERRITE USING MIXED CONTROL MODEL WITH CONSIDERATION OF DISLOCATION INTERACTION. Acta Metall Sin, 2015, 51(9): 1136-1144.
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Abstract During austenite to ferrite transformation, the lattice structure transforms from fcc to bcc, resulting in a clearly distinguishable austenite and ferrite interface. The short range diffusion of the Fe and C atoms across the interface causes its movement, referred to as interface migration. On the other hand, the C rejected by the ferrite during the austenite to ferrite transformation in Fe-C alloys accumulates ahead of the moving interface. This pile-up of C atom is dependent on the long range diffusion of C in austenite and also influences the ferrite growth kinetics. Experimental observations indicate that dislocations are always migrating with ledges during ledgewise growth. The local stress field of dislocations is considered to alter the solute concentration at the riser of ledges and causes a complex diffusion field interaction among ledges as they migrate. Some established works by other researchers have already taken the effect into consideration when studying phase transformation kinetics. However, these works were limited in diffusion control cases and could hardly explain some experimental results. In this work, a ledgewise growth model considering migration of austenite/ferrite interface, C diffusion in austenite and especially elastic interactions between dislocations moving with ferrite ledges was established, and all the simulated results were qualitatively similar to the reported experimental results. Calculated results showed that the C concentration at the riser of ledges was changed by the elastic stress of these dislocations, which would further change the growth behavior of ledges. In the growth behavior simulations of two ledges, the horizontal distance of the two ledges was found to be a key role to determine the growth kinetics. When the horizontal distance of two ledges was larger than the critical distance, an attractive phenomenon of the two ledges was found to decelerate the leading step; while a repulsive phenomenon of the two ledges which would accelerate the leading ledge if the horizontal distance was smaller than this value. Compared with the simulation results without considering elastic interactions between dislocations, however, in the growth behavior simulations of multi-ledge with elastic dislocation interactions, the coalescence behavior of ledges and growth rate of the leading step were both changed.
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Fund: Supported by National Natural Science Foundation of China (Nos.51171087 and 51471094) |
[1] | Zener C. J Appl Phys, 1948; 20: 950 | [2] | Kirkaldy J S. Can J Phys, 1957; 35: 435 | [3] | Kirkaldy J S. Can J Phys, 1957; 36: 907 | [4] | Coates D E. Metall Trans, 1972; 3: 1203 | [5] | Christian J W. The Theory of Transformations in Metals and Alloys. 3rd Ed., Oxford: Pergamon Press, 1975: 480 | [6] | Xu Z Y.Principle of Phase Change. Beijing: Science Press, 1988: 1 (徐祖耀. 相变原理. 北京: 科学出版社, 1988: 1) | [7] | Sietsma J, Van der Zwaag S. Acta Mater, 2004; 52: 4143 | [8] | Krielaart G P, Sietsma J, Van der Zwaag S. Mater Sci Eng, 1997; A237: 216 | [9] | Enomoto M. Acta Metall, 1987; 35: 935 | [10] | Enomoto M. Acta Metall, 1987; 35: 947 | [11] | Hoyt J J. Acta Mater, 2013; 61: 4953 | [12] | Yang Z Z, Li Z D, Liu Z Y, Liu Z Q, Xia Z X, Zhang C. Solid State Phenomena, 2011; 172: 1134 | [13] | Liu Z Q, Yang Z Z, Li Z D, Zhang C. Int J Miner Metall Mater, 2012; 19: 428 | [14] | Liu Z Y, Yang Z Z, Li Z D, Liu Z Q, Zhang C. Acta Metall Sin, 2010; 46: 390 (刘志远, 杨志刚, 李昭东, 刘振清, 张 弛. 金属学报, 2010; 46: 390) | [15] | Hirth J P. Metall Trans, 1991; 22A: 1331 | [16] | Kamat S V, Hirth J P. Acta Metall, 1994; 42: 3767 | [17] | Enomoto M, Hirth J P. Metall Mater Trans, 1996; 27A: 1491 | [18] | Pereloma E, Edmonds D V. Phase Transformations in Steels. Cambridge: Woodhead Publishing Ltd, 2012: 176 | [19] | Hirth J P, Lothe J. Theory of Dislocations. 2nd Ed., Melbourne: Krieger, 1992: 117 | [20] | Hillert M. Metall Mater Trans, 1975; 6A: 5 | [21] | Kinsman K R, Eichen E, Aaronson H I. Metall Trans, 1975; 6A: 303 | [22] | Andrews K W. Acta Metall, 1963; 11: 939 | [23] | K?ster W, Franz H. Metall Rev, 1961; 6: 1 | [24] | Eichen E, Aaronson H I, Pound G M, Trivedi R. Acta Metall, 1964; 12: 1298 | [25] | Simonen E P, Aaronson H I, Trivedi R. Metall Trans, 1973; 4: 1239 |
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