| Title |
Joint - Syposium on Fine - Grained Materials by the Phase Transformation Committee ( Eighth ) and the Ferrous Metallurgy Committee ( Second ) : Grain Growth and Modeling ; Microstructural Evolution of Mechanically Milled (Ti52Al48)100-xBx Alloys |
| Authors |
정현호(H . H . Chung) ; 표성규(Sung G . Pyo) ; 김상혁(Sang H . Kim) ; 황승준(S . J . Hwang) ; 김낙준(Nack J . Kim) |
| Abstract |
The main objective of this study is to investigate the microstructural evolution during mechanical milling of prealloyed (Ti_(52)Al_(48))_(100-x)B_x powders and also to investigate the effects of B contents and heat treatment on the microstructure of mechanically milled TiAl alloys. Microstructure of binary Ti_(52)Al_(48) Powders consists of grains of hexagonal phase whose structure is very close to Ti₂Al. (Ti_(52)Al_(48))_(95)B_5 powders contain TiB₂ in addition to matrix grains of hexagonal phase. The grain sizes in the as-milled powders of both alloys are nanocrystalline. The mechanically alloyed powders were consolidated by vacuum hot pressing (VHP) at 1000℃ for 2 hours, resulting in a material which is fully dense. Microstructure of consolidated binary alloy consists of γ-TiAl phase with dispersions of Ti₂AlN and A1₂O₃ phases located along the grain boundaries. Binary alloy shows a significant coarsening in grain and dispersoid sizes. On the other hand, microstructure of B containing alloy consists of γ-TiAl grains with fine dispersions of TiB₂ within the grains and shows the minimal coarsening during annealing. |