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Vol.50, No.7, 477 ~ 486, 2012
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| Title |
| Microstructure Evolution of Ti-6Al-4Fe-0.25Si through Aging Heat Treatment |
| 송용환 Yong Hwan Song , 강주희 Joo Hee Kang , 박찬희 Chan Hee Park , 김성웅 Seong Woong Kim , 현용택 Yong Taek Hyun , 강남현 Nam Hyun Kang , 염종택 Jong Taek Yeom |
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| Abstract |
| The effect of aging heat treatment on microstructure evolution of the Ti-6Al-4Fe-0.25Si alloy with an initial microstructure of an elongated alpha was investigated. Aging treatments of the samples were carried out at 550℃ for up to 100 hours. The microstructure of the 5 hours heat-treated sample consisted of alpha grains, beta matrix and some TiFe intermetallic compounds that were precipitated from the beta matrix. Increasing the aging time to 10 hours, most of the beta matrix was decomposed to very fine alpha grains (~ 0.5㎛) and TiFe, and thus the volume fraction of the beta matrix was significantly decreased. EBSD analysis revealed that newly formed tertiary-alpha-grains in the vicinity of TiFe had high angle boundaries with respect to the primary and secondary alpha grains. As a result of these phase transformations during aging, the fraction of the alpha/alpha grain boundary was increased while that of the alpha/beta phase boundary was decreased. |
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| Key Words |
| titanium, TiFe intermetallic compound, aging, precipitation, electron backscatter diffraction |
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