腐蚀促进位错发射、运动及SCC形核的TEM原位观察（Ti_3Al＋Nb──甲醇体系）

在ＴＥＭ中研究了Ｔｉ_３Ａｌ＋Ｎｂ在甲醇中的应力腐蚀开裂（ＳＣＣ）过程，结果表明，腐蚀过程能促进位错发射、增殖和运动；当其发展到临界条件时，纳米级应力腐蚀裂纹就在无位错区或裂尖形核。

IN SITU TEM OBSERVATION OF DISLOCATION EMISSION,MOTION AND SCC INITIATION IN Ti_3Al+Nb UNDER METHANOL CORROSION

The in situ TEM observations of dislocation emission,motion and initiation of nanocrack in Ti_3Al+Nb under methanol corrosion were carried out.Using a special constant displacement device,the dislocation coniguration change ahead of a loaded crack tip before and after anodic dissolution in methanol and the initiation,propagation of nanometre scale stress corrosion cracks have been observed.The results showed that localized anodic dissolution of Ti_3Al+Nb in methanol at room temperature facilitated dislocation emission,multiplication and motion.A nanocrack initiated in the dislocation free zone or at the blunted crack tip after dislocation emission, multiplication and motion reached a critical condition.