Browse > Article
http://dx.doi.org/10.5228/KSPP.2009.18.7.544

Low-Temperature Superplastic Deformation Behavior of Fine-Grained Ti-6Al-2Sn-4Zr-2Mo-0.1Si Alloy  

Park, C.H. (포항공과대학교 신소재공학과)
Lee, B. (포항공과대학교 신소재공학과)
Lee, C.S. (포항공과대학교 신소재공학과)
Publication Information
Transactions of Materials Processing / v.18, no.7, 2009 , pp. 544-549 More about this Journal
Abstract
This study aimed to elucidate the deformation mechanism during low-temperature superplasticity of fine-grained Ti-6Al-2Sn-4Zr-2Mo-0.1Si alloy in the context of constitutive equation. For this purpose, initial coarse equiaxed microstructure was refined to $2.2{\mu}m$ via dynamic globularization. Globularized microstructure exhibited large superplastic elongations(434-826%) at temperatures of $650-750^{\circ}C$ and strain rate of $10^{-4}s^{-1}$. It was found that the main deformation mechanism of fine-grained material was grain boundary sliding accommodated by dislocation motion with both stress exponent (n) and grain size exponent (p) values of 2. When the alpha grain size, not sub-grain size, was considered to be an effective grain size, the apparent activation energy for low-temperature superplasticity of the present alloy(169kJ/mol) was closed to that of Ti-6Al-4V alloy(160kJ/mol).
Keywords
Titanium Alloy; Superplasticity; Deformation Mechanism; Dynamic Globularization;
Citations & Related Records
Times Cited By KSCI : 1  (Citation Analysis)
연도 인용수 순위
1 H. Watanabe, T. Mukai, M. Kohzu, S. Tanabe, K. Higashi, 1999, Effect of temperature and grain size on the dominant diffusion process for superplastic flow in an AZ61 magnesium alloy, Acta Mater., Vol. 47, pp. 3753-3758   DOI   ScienceOn
2 J. S. Kim, J. H. Kim, Y. T. Lee, C. G. Park, C. S. Lee, 1999, Microstructural analysis on boundary sliding and its accommodation mode during superplastic deformation of Ti–6Al–4V alloy, Mater. Sci. Eng. A, Vol. 263, pp. 272-280   DOI   ScienceOn
3 Z. X. Guo, N. Ridley, 1987, Modeling of diffusion bonding of metals, Mater. Sci. Technol., Vol. 3, pp. 945-953   DOI   ScienceOn
4 L. Briottet, J. J. Jonas, F. Montheillet, 1996, A mechanical interpretation of the activation energy of high temperature deformation in two phase materials, Acta Mater., Vol. 44, pp. 1665-1672   DOI   ScienceOn
5 Y. G. Ko, C. S. Lee, D. H. Shin, S. L. Semiatin, 2006, Low-temperature superplasticity of ultrafine- grained Ti-6Al-4V processed by equal-channel angular pressing, Metall. Mater. Trans., Vol. 37A, pp. 381-391   DOI
6 C. H. Park, Y. G. Ko, J.-W. Park, C. S. Lee, 2008, Enhanced superplasticity utilizing dynamic globularization of Ti-6Al-4V alloy, Mater. Sci. Eng. A, Vol. A 496, pp. 150-158   DOI   ScienceOn
7 G. A. Sargent, A. P. Zane, P. N. Fagin, A. K. Ghosh, S. L. Semiatin, 2008, Low-temperature coarsening and plastic flow behavior of an alpha/beta titanium billet material with an ultrafine microstructure, Metall. Mater. Trans., Vol. 39A, pp. 2949-2964   DOI
8 M. L. Meier, D. R. Lesuer, A. K. Mukherjee, 1991, $\alpha$ Grain size and $\beta$ volume fraction aspects of the superplasticity of Ti-6Al-4V, Mater. Sci. Eng. A, Vol. A136, pp. 71-78   DOI   ScienceOn
9 T. Seshacharyulu, S. C. Medeiros, W. G. Frazier, Y. V. R. K. Prasad, 2000, Hot working of commercial Ti–6Al–4V with an equiaxed $\alpha$–$\beta$ microstructure: materials modeling considerations, Mater. Sci. Eng. A, Vol. A284, pp. 184-194   DOI   ScienceOn
10 C. H. Park, K.-T. Park, D. H. Shin, C. S. Lee, 2008, Microstructural mechanisms during dynamic globularization of Ti-6Al-4V alloy, Mater. Trans., Vol. 49, pp. 2196-2200   DOI   ScienceOn
11 J. H. Kim, S. L. Semiatin, C. S. Lee, 2003, Constitutive analysis of the high-temperature deformation of Ti-6Al-4V with a transformed misconstrue, Acta Mater., Vol. 51, pp. 5613-5626   DOI   ScienceOn
12 O. D. Sherby, J. Wadsworth, 1989, Superplasticityrecent advances and future directions, Prog. Mater. Sci., Vol. 33, pp. 169-221
13 H. Oikawa, T. Oomori, 1988, Steady state deformation characteristics $\alpha$-Ti-Al solid solutions, Mater. Sci. Eng. A, Vol. A104, pp. 125-130   DOI   ScienceOn
14 J. H. Kim, N. S. Reddy, J. T. Yeom, J. K. Hong, C. S. Lee, N.-K. Park, 2009, Microstructure prediction of two-phase titanium alloy during hot forging using artificial neural networks and FE simulation, Met. Mater. Int., Vol. 15, pp. 427-437   DOI   ScienceOn
15 M. T. Cope, D. R. Evetts, N. Ridley, 1986, Superplastic deformation characteristics of two microduplex titanium alloys, J. Mater. Sci., Vol. 21, pp. 4003-4008   DOI   ScienceOn
16 J. S. Kim, Y. W. Chang, C. S. Lee, 1998, Quantitative analysis on boundary sliding and its accommodation mode during superplastic deformation of two-phase Ti-6Al-4V alloy, Metall. Mater. Trans., Vol. 29A, pp. 217-226   DOI