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In this paper, the damage tolerance alloy of Ti-62222s has been studied, which was analysised by optical microstructure, mechanical properties testing, scanning electron microscopy analysis and other methods,in order to found the effect of different heat treatment on the microstructure and mechanical properties. It was discussed the Ti-62222s alloy’s genetic and evolution in phase change,and analysised the materials under different heat treatments,and found the effects on mechanical properties;The paper have shown the triple heat treatment of Ti-62222s Alloy, with increases of the cooling rate in second solution treatment, the content of stripα-phase was increased significantly, the aspect ratio of stripα-phase decreases; The study shows that with the basal meterial equiaxed structure of Ti-62222s alloy, with a lower solution treatment temperature (880℃,820℃) the changes in microstructure is small,and only have some changes in the secondaryα-phase, and the structer will still be equiaxed;At, the alloy microstructure evolution for the two-state organization with a 940℃,1h,FC heat treatment. With a double heat treatment of this alloy, only a small amount of metastableβphase can be retained in room temperture, and had some aging strength properties;With the second solution temperature decreased, the second solution in the same cooling rate, the alloy stripαphase were significantly reduced, but the width of the stripαincreased, especially in the low cooling rate of the second solution conditions. This is because with a high temperature solution treatment;After the furnace cooling in first solution treatment, and a low-temperature of second solution treatment followed by air cooling, which can ensured the aging strengthening effect,with reserved enough equiaxedαphase and a certain amount of stripα, but the strip length and width ofαphase becam larger, and easy to transgranular fracture;With the double heat treatment and aging (triple treatment) of Ti-62222s Alloy, the microstructure of theαstrip for the basket crossβtransformation matrix and a small amount of equiaxedαphase, the tensile fracture surface for the ductile fracture have some dimples. The tensile properties after aging was not sensitive to the aging temperature. Second solution temperature on the phase change was about the solution temperature as the heat treatment in the second variation of the reduction phase is:α"→α(920℃~940℃),α"→α+β(780℃~920℃); the Ti-62222s Alloy after the heat treatment with the X-rad analysis indicates that, the six groups of the samples with aging temperature as 500℃, 530℃, 550℃,570℃,590℃and 610℃will be affordαandβphase.
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