TC17钛合金疲劳裂纹扩展速率

Fatigue Crack Propagation Rate for TC17 Titanium Alloy

摘要:

研究了显微组织形态对TC17钛合金疲劳裂纹扩展速率的影响,并结合裂纹扩展路径进行了分析。结果表明,对于TC17合金,在裂纹扩展的第I阶段和第III阶段,等轴组织随着固溶温度的升高,扩展速率加快,显微组织对中速区的裂纹扩展速率影响不大；对两种片层组织结构的裂纹扩展速率分析结果表明,仅固溶态的组织在裂纹扩展的整个阶段具有较低的裂纹扩展速率,并且起裂区对应较高的应力强度因子,裂纹在固溶态组织中的扩展路径较固溶时效态的曲折。

关键词:TC17钛合金，疲劳裂纹扩展速率，裂纹扩展路径

Abstract:

Effect of microstructure on the fatigue crack propagation rates for TC17 Titanium alloy is studied in this paper, and crack growth path is analyzed. The results show that the crack growth rates increase with the temperature rising in the equiaxed structure on the step I and the step III during the crack growth for the TC17 titanium alloy, and the microstructure has fewer influences on step II on crack growth rate; The anysis conclusions of the crack growth rates for two different lamellar microstructres show that microstructure under the solution anneal has lower crack growth rates during the whole crack grwoth, the initia fracture zone matches higher sress intensity factor, and the crack growth path is more zigzag in solution anneal microstructure than that solution aging state.

Key words:TC17 titanium;alloy, fatigue;crack growth;rate, crack;growth path