Objective To provide useful references for the expansion of applications for TC18 titanium alloy as well as design and selection of product structure. Methods Atmospheric corrosion behaviors of TC18 titanium alloy in marine atmosphere environments for 6 years were investigated in virtue of the macro-micro corrosion morphology, static me-chanical property, fracture toughness and fatigue crack growth rate. Results In microscopic, there was no visible corro-sion as pitting. The tensile strength and fracture toughness decreased with the increase of marine atmosphere environment test time. The fracture toughness decreased by 6.7% after 4 years of test. The fracture morphology was quasi-cleavage;fatigue crack growth rate data and stress intensity factor range presented high linear relationship under da/dN-ΔK log-log plot for three test cycles of 2, 4 and 6 years. The parameters of Paris law da/dN=C(ΔK)nwere C1=5.846×10-11, n1=2.320, C2=6.01×10-14,n2=3.48,C3=1.81×10-13,n3=3.30.Conclusion TC18 titanium alloy exhibits low corrosion susceptibility in marine atmosphere environment.%目的 为TC18钛合金应用范围扩展和产品结构的设计与选材提供有益的借鉴和参考.方法 采用宏微观腐蚀形貌、静态力学性能、断裂韧度、疲劳裂纹扩展速率研究TC18钛合金在海洋大气环境下暴露6年的腐蚀行为.结果 TC18钛合金在微观形貌上未见点蚀坑等明显腐蚀,抗拉强度和断裂韧度随海洋环境试验时间的延长呈下降趋势,试验4年,TC18断裂韧度下降了6.7%,其断口形貌表现为准解理断口.在da/dN-ΔK双对数坐标中,2,4,6年三个试验周期中两者均呈现很好的线性关系,Paris 公式 da/dN=C(ΔK)n中,参数分别为C1=5.846×10-11,n1=2.320,C2=6.01×10-14,n2=3.48,C3=1.81×10-13,n3=3.30.结论 TC18钛合金在海洋大气环境下表现出较低的腐蚀敏感性.
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