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Vol.35, No.5, 558 ~ 566, 1997
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| Title |
| Effects of Al Content and Alloying Element Additions on the Crystallographic Factors and the Mechanical Properties of Υ-TiAl Intermetallic Compounds |
| 정재영 , 이언식 , 안상호 , 김성곤 , 박중근 Jae Young Jung , Eun Sik Lee , Sang Ho Ahn , Seong Kon Kim , Joong Keun Park |
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| Abstract |
| The effects of Al content and alloying elements on the crystallographic factors and the mechanical Properties of Ti-(47-54)Al and Ti-48Al-(1-3)M (M=Cr, Mn) intermetallic compounds have been investigated using optical microscopy, scanning electron microscopy, X-ray diffractometry, and compression testing. The γ grain size of heat-treated cast structure decreases with the decrease of Al content and the addition of Cr(or Mn). This is primarily due to the refinement of as-cast structure. In the heat-treated cast structure, the inhomogeneity of γ grain size is also related to the second phase particles, which are located within the dendrite core region. The variation of lattice parameters and tetragonality of γ phase as, a function of Al content shows a larger slope for the Ti-rich side than that for the Al-rich side in reference to the stoichiometric composition. This is believed to be primarily due to the difference of anti-site defect type. The hardness of Y phase is enhanced with the increase of the degree of non-stoichiometry. The variation of hardness is insensitive to the type of anti-site defect. The yield stresses of alloys containing Cr(or Mn) are mainly strengthened by the refinement of γ grain size. The ductility of γ-TiAl base intermetallic compounds depends primarily on the tetragonality rather than the unit cell volume change of γ phase. |
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