钛合金慢应变速率拉伸应力腐蚀行为研究

对TA31和TC4ELI两合金分别在干燥空气、3.5% NaCl环境下进行慢应变速率拉伸试验。结合应力-应变曲线以及断口宏观、微观组织分析两种材料的应力腐蚀敏感性。结果表明:在35℃、3.5%(w,下同) NaCl溶液、应变速率为10-6/s条件下,TC4ELI合金应力腐蚀敏感性较高,在5×10-7/s和5×10-6/s的应变速率下应力腐蚀敏感性较低;TA31合金在上述3种应变速率下应力腐蚀敏感性均较低;在3.5% NaCl环境中,TA31合金断口形貌较空气中试验的断口形貌无明显的变化,TC4ELI则出现较明显的解理面。 

Study on Tensile Stress Corrosion Behavior of Titanium Alloy at Slow Strain Rate

The tensile stress corrosion tests of TA31 and TC4ELI alloys at slow strain rates are carried out in dry air and 3.5% NaCl solution, respectively. Combined with the stress-strain curve, the macro and micro structures of the fractured surfaces, the stress corrosion sensitivity of the two alloys are analyzed. The results show that TC4ELI alloy has high stress corrosion sensitivity in 3.5% (w)NaCl solution at 35℃ and the strain rate of 10-6/s, when the strain rates are 5×10-7/s and 5×10-6/s, the stress corrosion sensitivity is low. TA31 alloy has low stress corrosion sensitivity at the above three strain rates. In 3.5% NaCl solution environment, the fracture morphology of TA31 alloy has no obvious change compared with that of air test, while TC4ELI has obvious cleavage surface.