阳极溶解促进α-Ti位错发射、运动导致SCC微裂纹形核

ANODIC DISSOLUTION-INDUCED DISLOCATION EMISSION AND MOTION FOR α-Ti RESULTING IN SCC MICROCRACK NUCLEATION

用激光云纹干涉法原位测量了应力腐蚀（ＳＣＣ）前后缺口前端位移场的变化并进行ＴＥＭ原位观察，结果表明，阳极溶 解能使块状试样缺口前端塑性区及其变形量增大当溶解促进的局部塑性变形发展到临界条件，就会导致ＳＣＣ微裂纹在无位错区中形 核α－Ｔｉ在甲醇溶液中表面钝化膜形成和保持过程中会在内界面产生较大的拉应力，它能协助外应力促进局部塑性变形，进而促进

The change in displacement field ahead of a loaded notch tip for a bulk specimen before and after stress corrosion cracking (SCC) was in situ measured by laser moire interferometer technique. The results showed that anodic dissolution could enlarge the plastic zone and increase the plastic stain ahead of the bulk specimen. The in situ TEM observation showed that when dissolution-enhanced local plastic deformation reached a critical condition, an SCC microcrack would nucleate in dislocation free zone (DFZ). The passive film--induced tensile stress generated during natural corrosion in methanol for α-Ti was measured by foil specimen. The result showed that a large tensile stress was developed in the surface layer during the initiation and development of the surface passive film for α-Ti in methanol. The extra tensile stress would assist the load stress during SCC to facilitate the local plastic deformation, then to induce SCC microcrack nucleation.