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Vol.43, No.11, 766 ~ 771, 2005
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| Title |
| Special Edition : Symposium on Mechanical Behavior of Materials(1) ; Self-Consistent Approach for the High-Temperature Deformation Behavior of Two Phase Ti-6Al-4V Alloy |
| 김정한 Jeoung Han Kim , 염종택 Jong Taek Yeom , 박노광 Nho Kwang Park , 이유환 You Hwan Lee , 이종수 Chong Soo Lee |
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| Abstract |
| Individual flow behavior of a and β, phases in Ti-6Al-4V alloy was analyzed in the context of self-consistent approach. For this purpose, high temperature compression tests were conducted at various temperature ranges using single-phase α(Ti-7.0Al-1.5V), and two-phase Ti-6Al-4V alloy with an equiaxed microstructure. The individual flow behavior of a phase was deduced from the experimental results of single-phase alloy whose chemical composition is close to that of phase in Ti-6Al-4V. On the other hand, the flow behavior of β phase was calculated using self-consistent approach. From the results, it was found that the flow stress of α phase was higher than that of β, phase above 750℃, but the former revealed lower strength than the latter below 650℃. It was found that the relative strength and strain rate ratio between α and β, phase significantly varied with temperature. From this approach, the mode for grain matrix deformation was proposed as a mixed type of both iso-stress and iso-strain rate modes. The results of present approach were applied to predicted the flow behavior of Ti-alloys on the basis of phase volume fraction. Besides, the source of strength softening caused by temperature rise was examined. The increase of soft β, phase volume fraction plays significant role in flow stress decrease as well as easy slip transmission due to temperature rise. |
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| Key Words |
| Ti-6Al-4V, Self-consistent, Flow behanvior, Phase volume fraction, Dislocation glide |
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