材料期刊网

在350～500℃范围内研究了Ti-679合金的热盐应力腐蚀性能。实验表明合金的显微组织对热盐应力腐蚀的敏感性有很大的影响,在相同的热暴露条件下α+β相区热处理试样的临界应力比β相区热处理的要高。试验结果也表明,表面存在压应力的试样的临界应力高于无压应力者。用离子探针对断口表而进行的测定显示出在裂纹中有氢的大量富集,这表明钛合金在受热盐应力腐蚀过程中所产生的并随后被吸收的氢是开裂的主要原因。

It has been proved that most of the titanium alloys are susceptible to the so-called hot salt stress corrosion cracking under the combined action of high temperature, halide salt and stresses.In this paper the susceptibility of hot salt stress corrosion cracking of titanium alloy Ti-679 was investigated in the temperature range of 350～500°C.Experimental studies show that the microstructure of the alloy has pronounced effect on the susceptibility of H.S.S.C.C.It was shown that the threshold stress for H.S.S.C.C.of the specimens with α+β annealed structure was higher than that of the specimens with β annealed structure under the same hot exposure conditions.Experimental results also proved that the threshold stress of the specimens with compressive stress on the surface was higher than that of the specimens without it.Ion microprobe scanning analyses on the fractured surface showed that hydrogen was greatly concentrated at the crack surface and that hydrogen produced during the stress corrosion of titanium alloy by halide salt and subsequently absorbed by the alloy was responsible for cracking.