【摘 要】
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The effect of heat treatment on the microsructure evolution of a high Nb containing TiAl alloy has been studied.The results indicate thatβ-segregation,α-segre
【机 构】
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State Key Laboratory for Advanced Metals and Materials,University of Science and Technology Beijing,
论文部分内容阅读
The effect of heat treatment on the microsructure evolution of a high Nb containing TiAl alloy has been studied.The results indicate thatβ-segregation,α-segregation and S-segregation in the as-cast and as-forged alloys can be effectively eliminated at the temperature above Ta (1350-1400℃) for long holding time (12-24h) and the full lamellar (FL) microstructure is gained.For the two alloys,the lamellar colony sizes are 120 μm and 2000μm,respectively after heat treatment at 1400℃ for 12 h.Meanwhile,the sizes are 210μm and 3000μm,respectively at 1350℃ for 24 h.To get a fine homogenous microstructure,the primary as-cast alloy is first subjected to preheat treatment for eliminating the segregations.After the preheat treatment,the alloy is processed by the multi-step canned forging to attain the microstructure with free grain size.
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