| Abstract |
| The main objective of this study is to investigate the microstructural evolution during mechanical milling of prealloyed (Ti52Al49)95B5 powders and also to investigate the effects of B contents, mechanical milling process and the heat treatment on the microstructure of mechanically milled TiAl alloys. γ-(Ti52Al48)95B5 alloys have been produced by mechanical milling in an attritor mill using prealloyed powders. The grain sizes of the as-milled powders are nanocrystalline. It has been shown that the initial γ phase in as-melt extracted state becomes disordered by mechanical milling. In addition, there is a formation of the amorphous phase with the same composition as the disordered γ phase. Disordered γ and amorphous phases eventually transforms to the nanocrystalline Ti-Al hcp solid solution after the completion of milling. The nature of the final phase depends on the relative stabilities of various phases, modified by the deformation induced by mechanical milling. The mechanically milled (Ti52Al48)95B5 powders are consolidated by vacuum hot pressing at 1000℃ for 2 hours. Microstructure of as-pressed alloys consists of (α2+γ) phase with fine dispersion of TiB2 and TiB phase. |
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| Key Words |
| Microstructural evolution, Mechanical milling, TiAl Alloy, Nanocrystalline, TiB2, TiB, Ti-Al hcp solid solution |
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