含缺口TC21钛合金腐蚀疲劳性能分析

Analysis of Corrosion Fatigue Properties of Notched TC21 Titanium Alloy

摘要:

研究了TC21钛合金缺口试样在两种腐蚀环境（油箱积水、3.5%NaCl水溶液）与室温空气环境下的疲劳性能与断裂机理。并与光滑试样在室温空气环境下疲劳性能进行对比。结果表明，室温空气环境下，当两种试样疲劳寿命均达到5×105次循环时，缺口试样的循环应力值较光滑试样下降了52.7%；相同环境下随着应力水平降低，试样疲劳寿命增加；相同应力条件下，3.5% NaCl水溶液环境下试样疲劳寿命最低，油箱积水环境下次之，室温空气中TC21钛合金试样疲劳寿命最高；当应力较低时，差异更为显著。在腐蚀环境下，溶液中离子与金属原子发生电化学反应，加速了裂纹的萌生与扩展，3.5% NaCl水溶液中离子浓度较大，电化学反应更为剧烈

Abstract:

The fatigue properties and fracture mechanism of TC21 titanium alloy notched specimens in two kinds of corrosive environments (tank water, 3.5% NaCl aqueous solution) and room temperature air environment were studied. The fatigue properties of the smooth samples were compared in a room temperature air environment. The results show that when the fatigue life of both samples reaches 5×105 cycles, the cyclic stress value of the notched sample is 52.7% lower than that of the smooth sample; As the stress decreases in the same environment, the fatigue life of the alloy increases; Under the same stress conditions, the alloy has the lowest fatigue life under salt water environment, and the tank water storage environment is next. The fatigue life of TC21 alloy is the highest under room temperature air; When the stress is low, the difference is more significant. In the corrosive environment, the ions in the solution react with the metal atoms electrochemically, which accelerates the initiation and expansion of the crack. The concentration of ions in the 3.5% NaCl aqueous solution is larger and the electrochemical reaction is more intense.