Microstructural evolution of a PM TiAl alloy during heat treatment in α+γ phase field  

作　　者：SU Meike  ZHENG Lijing  LANG Zebao  YAN Jie  ZHANG Hu  

机构地区：School of Materials Science and Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100191, China[1] Aerospace Research Institute of Materials & Processing Technology, Beijing 100076, China[2]

出　　处：《Rare Metals》2012年第5期424-429,共6页稀有金属（英文版）

基　　金：supported by the National Natural Science Foundation of China (No. 51101003)

摘　　要：In this study, the effect of temperatures and cooling rates of heat treatment on the microstructure of a powder metallurgy (PM) Ti-46Al-2Cr-2Nb-(B,W) (at.%) alloy was studied. Depending on the cooling rate and temperature, the different structures were obtained from the initial near-γ (NG) microstructures by heat treatment in the α+γ field. The results show that the microstructures of samples after furnace cooling (FC) consist primarily of equiaxed γ and α 2 grains, with a few grains containing lamellae. Duplex microstructures consist mainly of γ grains and lamellar colonies were obtained in the quenching into another furnace at 900°C (QFC) samples. However, further increasing of the cooling rate to air cooling (AC) induces the transformation of α→α_2 and results in a microstructure with equiaxed γ and α_2 grains, and no lamellar colonies are found.In this study, the effect of temperatures and cooling rates of heat treatment on the microstructure of a powder metallurgy (PM) Ti-46Al-2Cr-2Nb-(B,W) (at.%) alloy was studied. Depending on the cooling rate and temperature, the different structures were obtained from the initial near-γ (NG) microstructures by heat treatment in the α+γ field. The results show that the microstructures of samples after furnace cooling (FC) consist primarily of equiaxed γ and α 2 grains, with a few grains containing lamellae. Duplex microstructures consist mainly of γ grains and lamellar colonies were obtained in the quenching into another furnace at 900°C (QFC) samples. However, further increasing of the cooling rate to air cooling (AC) induces the transformation of α→α_2 and results in a microstructure with equiaxed γ and α_2 grains, and no lamellar colonies are found.

关 键 词：γ-TiAl-based alloys powder metallurgy heat treatment duplex structure phase volume fractions 

分 类 号：TG166.5[金属学及工艺—热处理]