摘要
研究了Ｔｉ－２４Ａｌ－ｌｌＮｂ合金中Ｔｉ３Ａｌ＋Ｎｂ金属间化合物在甲醇溶液中的应力腐蚀及室温氢致开裂的规律，探讨了组织结构的影响．结果表明，Ｔｉ３Ａｌ＋Ｎｂ在甲醇溶液中应力腐蚀敏感性很高，不向组织应力腐蚀断裂归一化门槛值为而ｋ（ＩＳＣＣ）／ＫＣ＝０．５３－０．６９；应力腐蚀裂纹止裂门槛值为Ｋ（ＩＳＣＣ）／Ｋ（ｌｉ）＝０．６１－０．７９．Ｔｉ３Ａｌ＋Ｎｂ在室温动态充氢时能发生氢致开裂，门槛值和应力腐蚀相近，但裂纹扩展速率或断裂时间比应力腐蚀要慢１－３个数量级．两者断口形貌也不相同．发现了相界应力腐蚀现象．对固溶后炉冷试样，当ＫＩ较低时，应力腐蚀裂纹优先沿α２／β相界形核和扩展，从而获得相界应力腐蚀断口．如固溶后空冷或ＫＩ较高，则不出现相界应力腐蚀．
Stress corrosion cracking(SCC) in the methanol solution containing 0.6MKCI and hydrogen induced cracking(HIC) at room temperature for the titanium aluminide Ti-24Al-llNb were studied.It was found that SCC of the Ti-24Al-llNb alloy in the methanol solution is very sensitive and the normalized threshold stress intensity of SCC for vavious microstructures are Klscc/Kc=0.53-0.69(constant load specimen) and KISCC/Klc-0.61-0.79(WOL constant deflection specimen),respectively.The threshold stress intensity of HIC during dynamic charging at room temperature is close upon that of SCC,but da/dt or fracture time of HIC is one to three orders lower than that of SCC and the fracture surface for HIC is also different to that for SCC.A kind of interphase SCC for the Ti-24Al-llNb alloy in the methanol solution has been found.For the furnace cooled specimens with low KI,SCC initiated and propagated preferentially along the α2/βinterphase boundaries.There are no interphase SCC for the air cooled specimens or for the furnace cooled specimen with high KI.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
1994年第1期A035-A043,共9页
Acta Metallurgica Sinica
基金
国家自然科学基金
关键词
甲醇
应力腐蚀
相界
金属间化合物
Titanium Aluminide,SCC in methonal,HIC,interphase SCC
