显微组织对TC18钛合金高温力学性能的影响

Effects of Microstructure on High Temperature Mechanical Properties of TC18 Titanium Alloy

研究了等轴组织和片层组织TC18钛合金的高温拉伸和高温蠕变性能。结果表明,片层组织TC18钛合金的强度高于等轴组织,但塑性较差,而等轴组织TC18钛合金的综合性能较好。片层组织TC18钛合金的抗蠕变性能要好于等轴组织。在350~400℃时,其应力指数n小于2,蠕变机制为位错滑移;在450℃时,其应力指数n等于3,蠕变机制为位错攀移。

High temperature tensile and creep behavior of TC 18 alloys with equiaxed and lamellar microstructure were studied. The results show that TC18 alloy with the lamellar microstructure has higher strength compared with equiaxed microstructure, but the plasticity is lower. TC18 alloy with equiaxed microstructure has good combination property. TC18 alloy with lamellar microstmcture has higher creep resistance compared with equiaxed microstmcture. At 350-400℃, the creep of TC18 alloy with lamellar microstructure is dominantly controlled by dislocation sliding based on low stress exponent n 〈2. When increasing temperature to 450 ℃, the major creep mechanism changes into dislocation climbing and the stress exponent is equal to 3.