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Vol.36, No.7, 1092 ~ 1102, 1998
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| Title |
| Microstructural Evolution in a Ti-46.6Al-2Mo-1.4Mn Intermetallic Alloy Produced by Hot Extrusion of Elemental Powders |
| 표성규 Sung G. Pyo , 최성무 S. M. Choi , 황선근 S. K. Hwang , 김낙준 Nack J. Kim |
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| Abstract |
| The present study is concerned with nucleation and growth of α phase during heat treatment in TiAl-Mo-Mn intermetallic alloy processed by hot extrusion of elemental powders. TEM and X-ray diffraction analysis show that the microstructure of as-hot extruded alloy consists of γ, α2 and B2 phases. The volume fraction of α2 and B2 phases are 16% and 20%, respectively. It shows that the B2 phase which contain significant amount of Mo have orientation relationship with γplates inside them. Microstructural evolution during heat treatment reveals that the α2 phase nucleates and grows in lamellar form by edgewise and sidewise mechanism. Edgewise growth of α2 phase is more rapid than the sidewise growth due to the coherent interface between α2 and γ phases along the sidewise direction, Sidewise growth of α2 phase occurs by ledge mechanism. It has been shown that the α phase nucleates in γ plates located at thy lamellar boundaries and grows along the direction which can make incoherent interface. γphase present in the B2 phase affects the growth of α phase by providing the preferential site for a growth. |
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| Key Words |
| Powder Metallurgy, Hot extrusion, TiAl, B2, Incoherent growth |
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