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采用慢应变速率拉伸(SSRT)的方法,研究国产690合金分别在316℃含100 mg/L Cl-、1000 mg/L Cu2+以及100 mg/L Cl-与1000 mg/L Cu2+混合溶液中的应力腐蚀行为。通过激光共聚焦显微镜和扫描电镜观察断裂后试样的表面、断口以及纵剖面的微观形貌。结果表明:国产690合金在同时含Cl-与Cu2+的溶液中具有较高的应力腐蚀敏感性;断裂试样表面出现了大量的腐蚀坑,断口呈明显的脆性断裂特征,且在表面蚀坑的底部发现了沿晶应力腐蚀裂纹的萌生。由此证明Cl-与Cu2+对国产690合金应力腐蚀的协同作用,并初步探讨了其作用机理。
The effects of 100 mg / L Cl-, 1000 mg / L Cu2 + and 100 mg / L Cl- and 1000 mg / L Cu2 + mixed solution on the domestic 690 alloy at 316 ℃ were studied by slow strain rate tensile test (SSRT) Stress corrosion behavior. The microstructures of the surface, fracture and longitudinal section of the specimen after fracture were observed by laser scanning confocal microscope and scanning electron microscope. The results show that the domestic 690 alloy has high sensitivity to stress corrosion in the solution containing both Cl- and Cu2 +; a large number of corrosion pits appear on the surface of the fracture specimen, the fracture shows obvious brittle fracture characteristics, and the surface corrosion pits Found at the bottom of the intergranular stress corrosion cracking initiation. The synergistic effect of Cl- and Cu2 + on the stress corrosion cracking of domestic 690 alloy was proved, and the mechanism of action was also discussed.