A 0.7 mm-thick wavy γ-TiAl sheet with fully lamellar microstructure was fabricated by hot pressing Ti/Al alternate foils with heat treatment of 640 °C, 15 h＋850 °C, 35 h＋1350 °C, 2 h. The intermetall...A 0.7 mm-thick wavy γ-TiAl sheet with fully lamellar microstructure was fabricated by hot pressing Ti/Al alternate foils with heat treatment of 640 °C, 15 h＋850 °C, 35 h＋1350 °C, 2 h. The intermetallic compounds formed during heat treatments were identified by scanning electron microscopy （SEM） and X-ray diffraction （XRD）. TiAl3 was the only observed phase at the Ti/Al interface when Al foils were not consumed. After being annealed at 850 °C for 35 h, the microstructure was composed of α-Ti, α2-Ti3Al, γ-TiAl and TiAl2. A fully lamellar microstructure formed after annealing at 1350 °C. Most of the angles between the lamellar interface and the sheet plane are below 30°. Using thinner starting foils is favorable to produce sheets with fine microstructure.展开更多
Reaction behaviors occurring in Ti/Al foil metallurgy were systematically investigated.Particular emphasis was focused on the reaction between solid Al and Ti as well as subsequent reaction between TiAland Ti layer.In...Reaction behaviors occurring in Ti/Al foil metallurgy were systematically investigated.Particular emphasis was focused on the reaction between solid Al and Ti as well as subsequent reaction between TiAland Ti layer.In the solid reaction between Al and Ti,the presence of residual Al is mainly caused by inhomogeneous growth of TiAllayer and micro-voids existing at the interface.However,through reaction between molten Al and Ti,TiAl/Ti multilayer can be achieved with complete consumption of Al.During subsequent high-temperature heat treatment,TiAl/Ti multilayer will eventually turn into TiAl/TiAl multilayer accompanying with simultaneous formation and successive disappearance of intermediate phases,such as TiAland TiAl.Moreover,it is found that the growth direction of TiAl layer changes as a function of annealing time between different couples in multi-intermetallics system.展开更多
基金Project (50771041) supported by the National Natural Science Foundation of ChinaProject (05-0350) supported by the New Century Excellent Talents in University, China
文摘A 0.7 mm-thick wavy γ-TiAl sheet with fully lamellar microstructure was fabricated by hot pressing Ti/Al alternate foils with heat treatment of 640 °C, 15 h＋850 °C, 35 h＋1350 °C, 2 h. The intermetallic compounds formed during heat treatments were identified by scanning electron microscopy （SEM） and X-ray diffraction （XRD）. TiAl3 was the only observed phase at the Ti/Al interface when Al foils were not consumed. After being annealed at 850 °C for 35 h, the microstructure was composed of α-Ti, α2-Ti3Al, γ-TiAl and TiAl2. A fully lamellar microstructure formed after annealing at 1350 °C. Most of the angles between the lamellar interface and the sheet plane are below 30°. Using thinner starting foils is favorable to produce sheets with fine microstructure.
基金financially supported by the National Basic Research Program of China(No.2011CB605501)the National Natural Science Foundation of China(Nos.U1204508 and 51171015)the Project of State Key Laboratory for Advanced Metals and Materials,University of Science and Technology Beijing(No.2012Z-11)
文摘Reaction behaviors occurring in Ti/Al foil metallurgy were systematically investigated.Particular emphasis was focused on the reaction between solid Al and Ti as well as subsequent reaction between TiAland Ti layer.In the solid reaction between Al and Ti,the presence of residual Al is mainly caused by inhomogeneous growth of TiAllayer and micro-voids existing at the interface.However,through reaction between molten Al and Ti,TiAl/Ti multilayer can be achieved with complete consumption of Al.During subsequent high-temperature heat treatment,TiAl/Ti multilayer will eventually turn into TiAl/TiAl multilayer accompanying with simultaneous formation and successive disappearance of intermediate phases,such as TiAland TiAl.Moreover,it is found that the growth direction of TiAl layer changes as a function of annealing time between different couples in multi-intermetallics system.
