中國有色金屬學(xué)報(bào)(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 22 No. 3 March 2012 |
mechanical properties of melt-spun TiAl alloys
（1. State Key Laboratory for Advanced Metals and Materials,
University of Science and Technology Beijing, Beijing 100083, China;
2. School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China）
Abstract:A TiAl alloy from pulverized rapidly solidified ribbons with the composition of Ti−46Al−2Cr−4Nb−0.3Y (mole fraction, %) was processed by spark plasma sintering (SPS). The effects of sintering temperature on the microstructure and mechanical properties were studied. The results show that the microstructure and phase constitution vary with sintering temperature. Sintering the milled powders at 1200 °C produces fully dense compact. Higher sintering temperature does not improve the densification evidently. The dominant phases are γ and α2 in the bulk alloys sintered at 1200 °C. With higher sintering temperature, the fraction of α2 phase decreases and the microstructure changes from equiaxed near γ grain to near lamellar structure, together with a slight coarsening. The bulk alloy sintered at 1260 °C with refined and homogeneous near lamellar structure reveals the best overall mechanical properties. The compressional fracture stress and compression ratio are 2984 MPa and 41.5%, respectively, at room temperature. The tensile fracture stress and ductility are 527.5 MPa and 5.9%, respectively, at 800 °C.
Key words: TiAl alloy; rapid solidification; spark plasma sintering; microstructure; mechanical properties
