典型材料在腐蚀环境下裂纹扩展速率研究

Study on Crack Growth Rate of Typical Materials in Corrosive Environment

目的:研究7140-T7451厚板铝合金材料在腐蚀环境下的裂纹扩展速率。方法:通过开展7140-T7451厚板铝合金材料在室温大气、潮湿空气、3.5%NaCl溶液和油箱积存水4种环境下的裂纹扩展,采用Paris公式进行曲线拟合得到7140-T7451厚板铝合金在4种环境下的裂纹扩展曲线,并采用《民机结构耐久性与损伤容限设计手册》中方法,分析得到7140-T7451厚板铝合金在潮湿空气、3.5%NaCl溶液和油箱积存水3种腐蚀环境下的影响因子。结果:研究表明,3.5%NaCl溶液和油箱积存水对7140-T7451厚板铝合金裂纹扩展速率的影响较大。结论:对于7140-T7451铝合金材料,潮湿空气环境影响因子=0.88,3.5%NaCl溶液环境影响因子=0.73,油箱积存水环境影响因子=0.75。

Objective: To study the crack growth rate of 7140-t7451 thick aluminum alloy in corrosive environment. Methods: By carrying out the crack propagation of 7140-t7451 thick plate aluminum alloy material in four environments including room temperature atmosphere, moist air, 3.5 % nacl saline water and fuel tank accumulated water, the curve fitting is carried out by using Paris formula to obtain its crack propagation curve in the four environments, and the method in Civil Aircraft Structure Durability and Damage Tolerance Design Manual is used to analyze and obtain the influence factors of 7140-t7451 thick plate aluminum alloy in the three corrosive environments including moist air,3.5 %NaCl saline solution and water accumulated in the fuel tank. Results: The research shows that 3.5 %NaCl saline solution and water accumulated in the fuel tank have a great influence on the crack growth rate of 7140-t7451 thick aluminum alloy plate. Conclusion: For 7140-t7451 aluminum alloy material,the environmental impact factor of moist air is =0.88, the environmental impact factor of 3.5 % NaCl saline solution is =0.73, and the environmental impact factor of water accumulated in the fuel tank is =0.75.