固溶时效处理对Ti-5322钛合金组织与性能的影响

Effect of solution and aging treatment on microstructure and tensile properties of Ti-5322 alloy

通过对Ti-5322合金板材进行固溶时效处理,发现在相变点以下的α+β两相区温度固溶时,初生α相随固溶温度的升高而减少,β相所占体积分数升高;在相变点以上的β单相区温度固溶时,初生α相全部溶入β基体之中,温度越高,晶粒越粗大。在510~590℃时效处理过程中,细小弥散的板条状次生α相在β基体内析出,起到了析出强化作用,且随着时效温度的升高,次生α相长大,所占体积分数减少,导致合金的强度下降,塑性升高。对Ti-5322合金热处理后的试样进行室温拉伸试验,发现与β单相区温度固溶时效相比,合金在α+β两相区温度固溶及不同温度时效处理后强度与塑性的匹配更加优良,因此选择在两相区进行固溶处理是最合适的,最佳工艺为870℃×1h固溶+550℃×6 h时效。

Through solution and aging treatment,the microstructure and tensile properties of Ti-5322 alloy were studied.The results show that when the solution treatment temperature is below the transformation point,the primaryαphase decreases with the increase of solution treatment temperature,and the volume fraction of theβphase increases.When the solution treatment temperature is above the transformation point,the primaryαphase is completely dissolved into theβphase,and the higher the temperature,the coarser the grains.During the aging at 510-590℃,the secondaryαphase plates precipitate in theβmatrix,which plays a precipitation strengthening role.As the aging temperature increases,the secondaryαphase grows up and its volume fraction is reduced,leading to a decrease in the strength and an increase in the plasticity of the alloy.The room temperature tensile test shows that compared with the solution treatment in β single-phase region then aging,the strength and plasticity of the alloy are more excellent after solution treatment in theα+βtwo-phase region and aging,so it is most suitable to select the solution treatment in the two-phase region,and the optimum process is solution at 870℃for 1 h and aging at550℃for 6 h.