| The present study is to investigate the growth behavior of intermetallic phases in multilayered Ti/TiAl_3 sheets fabricated by hot rolling. When these sheets were heat-treated at 1000℃, interfacial phases such as Ti_3Al, TiAl, and TiAl_2 were grown consuming Ti and TiAl_3. As the heat treatment proceeded, TiAl was grown consuming TiAl_2, thereby finally fabricating multilayered sheets composed of Ti_3Al and TiAl. Conventional lamellar structure composed of Ti_3Al and TiAl could also be fabricated by heat treatment of multilayered Ti/TiAl_3 sheets at 1400℃. The growth rate and activation energy of interfacial phases were obtained from their growth behavior. The results indicated that the growth of intermetallic phases was mainly controlled by volume diffusion than by grain boundary diffusion. The formation process of the multilayered sheets and the formation mechanism of interfacial phases were elucidated, and an idea to fabricate multilayered or bulk Ti aluminide sheets by hot rolling and heat treatment was eventually suggested in this study. |
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