The heat treatment, including two steps, was proposed to obtain Fine Fully Lamellar (FFL) microstructure on TiAl containing minor Ni. The first step was in (a+y) phase region to get Duplex (DP) microstructure, and the...The heat treatment, including two steps, was proposed to obtain Fine Fully Lamellar (FFL) microstructure on TiAl containing minor Ni. The first step was in (a+y) phase region to get Duplex (DP) microstructure, and the second step was in a phase region transforming DP microstructure into FFL microstructure. The effect of heat treatment on microstructures and properties was studied. The results showed that the static recrystallization kinetics in (a+y) phase region took the form of Avrami equitation, and the remnant lamellae in DP microstructure were detrimental to room temperature tensile properties. The FL microstructures were obtained after heat treatment in phase region using DP microstructure, the uniform FFL microstructure was beneficial to comprehensive properties.展开更多
The oxidation behavior of high speed steel (HSS) was researched by high temperature thermo balance at 500 to 800 °C in water vapor. The morphology was observed by scanning electron microscope, the microstructure ...The oxidation behavior of high speed steel (HSS) was researched by high temperature thermo balance at 500 to 800 °C in water vapor. The morphology was observed by scanning electron microscope, the microstructure of oxide scale was analyzed by energy dispersive spectrometer and X-ray diffraction spectrum. The results indicate that the mass gain of HSS increases with oxidation temperature rising, the effect of oxidation temperature on the morphology is obvious, water vapor temperature only affects mass gain and affects hardly morphology of oxide scale at the same oxidation temperature. The relevant oxidation mechanisms are also discussed.展开更多
基金National High-Tech Projects(863 program)supported this research under the contract number 2001AA301080 and 2002AA305209 respectively.
文摘The heat treatment, including two steps, was proposed to obtain Fine Fully Lamellar (FFL) microstructure on TiAl containing minor Ni. The first step was in (a+y) phase region to get Duplex (DP) microstructure, and the second step was in a phase region transforming DP microstructure into FFL microstructure. The effect of heat treatment on microstructures and properties was studied. The results showed that the static recrystallization kinetics in (a+y) phase region took the form of Avrami equitation, and the remnant lamellae in DP microstructure were detrimental to room temperature tensile properties. The FL microstructures were obtained after heat treatment in phase region using DP microstructure, the uniform FFL microstructure was beneficial to comprehensive properties.
文摘The oxidation behavior of high speed steel (HSS) was researched by high temperature thermo balance at 500 to 800 °C in water vapor. The morphology was observed by scanning electron microscope, the microstructure of oxide scale was analyzed by energy dispersive spectrometer and X-ray diffraction spectrum. The results indicate that the mass gain of HSS increases with oxidation temperature rising, the effect of oxidation temperature on the morphology is obvious, water vapor temperature only affects mass gain and affects hardly morphology of oxide scale at the same oxidation temperature. The relevant oxidation mechanisms are also discussed.
