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测试表明,690TT合金划痕周围形成了加工硬化区,范围可达100μm.TEM及EBSD-OIM组织观察发现,划痕沟槽处的基体组织出现了一定程度的纳米化.在330℃碱溶液中的浸泡实验表明,划伤诱发了690TT合金应力腐蚀裂纹的萌生和扩展.划伤过程中形成的变形晶界、孪晶界以及产生的微观裂纹成为应力腐蚀裂纹优先萌生的位置.Pb的存在使氧化膜变得疏松,加速了基体的溶解和氧化.随着溶液中Pb含量的增加.划伤诱发的应力腐蚀裂纹长度随之增加.690TT合金表面划伤严重降低了材料抵抗应力腐蚀开裂的能力.
The results show that the work-hardened zone around the scratch of 690TT alloy is formed in the range of up to 100μm.TEM and EBSD-OIM microstructure shows that the matrix structure at the scratched groove has a certain degree of nanocrystallization.In 330 ℃ alkaline solution Immersion experiments showed that scratch induced the initiation and propagation of stress corrosion cracking of 690TT alloy.The deformed grain boundaries, twin boundaries and micro-cracks formed during scratching became the preferential sites of stress corrosion cracking.The presence of Pb The oxide film becomes loose and accelerates the dissolution and oxidation of the matrix.With the increase of Pb content in the solution, the length of the stress corrosion cracking induced by the scratch increases.Cutting on the surface of the90TT alloy severely reduces the ability of the material to resist stress corrosion cracking .