-3、1×10-4和5×10-5 s-1條件下的高溫力學(xué)性能，并討論了相應(yīng)的變形機(jī)理。結(jié)果表明，在高溫或低應(yīng)變率下，Ti-45Al-7Nb合金的極限拉伸強(qiáng)度逐漸降低，但伸長(zhǎng)率顯著增加。由于細(xì)小晶粒容易實(shí)現(xiàn)變形和協(xié)調(diào)，其伸長(zhǎng)率明顯高于粗晶粒合金。高溫拉伸后，合金在裂縫處形成大量的空洞，并在裂縫前部形成大量垂直于拉伸方向的長(zhǎng)裂紋。此外，晶界的滑動(dòng)、晶粒的孿生和動(dòng)態(tài)再結(jié)晶也導(dǎo)致了合金變形，從而提高了微觀組織的延展性。;The duplex Ti-45Al-7Nb (at%) alloys with equiaxed fine grains were prepared by powder metallurgy method. The high temperature mechanical properties of the alloys at 900, 950, and 1000 °C under the strain rates of 1×10-3, 1×10-4, and 5×10-5 s-1 were investigated, and the corresponding deformation mechanism was also discussed. Results show that the tensile strength is decreased whereas the elongation is greatly increased at elevated temperatures or under decrescent strain rates. Since the small grains are easy to achieve deformation and coordination, the elongation of the small grain alloys is significantly higher than that of coarse grain alloys. The alloys form a large number of voids at the fractures after high temperature tensile. Long cracks perpendicular to the tensile direction are formed at the front fracture. Besides, the grain boundary sliding, grain twinning, and dynamic recrystallization also lead to the deformation of alloys, thus improving the microstructure ductility."/>