航空紧固件用Ti-5553合金的组织和性能

发布时间：2018-05-18 03:35

  本文选题：高强钛合金 + 紧固件　； 参考：《材料工程》2017年10期

【摘要】：采用扫描电镜和透射电子显微镜研究不同热处理制度对Ti-5553高强钛合金显微组织与力学性能的影响。结果表明:在(α+β)两相区进行固溶处理时,随着固溶温度的升高,Ti-5553合金组织中的初生α相含量逐渐减少,β相的尺寸和体积分数均增加,合金强度逐渐降低。时效后β基体发生转变,晶界和晶内析出大量次生α相。次生α相的尺寸对力学性能产生重要影响,随着时效温度的升高,次生α相逐渐粗化,导致抗拉强度逐渐下降。1240MPa级航空紧固件用Ti-5553的固溶温度应选择Tβ以下,使组织中留有足够的β相,从而时效时在β相中有大量次生α相析出,获得需要的高强度。同时,保留一定含量的初生α相,以便获得良好的塑韧性。经810~820℃,1.5h,水淬+510℃,10h,空冷热处理后,合金可以获得较好的综合性能,抗拉强度达1500MPa,伸长率达14.8%,断面收缩率为38.6%。固溶和时效态的拉伸断口均存在大量韧窝,材料具有良好的塑韧性。
[Abstract]:The effects of heat treatment on the microstructure and mechanical properties of Ti-5553 high strength titanium alloy were studied by scanning electron microscopy (SEM) and transmission electron microscope (TEM). The results show that the content of primary 伪 phase in the microstructure of Ti-5553 alloy decreases with the increase of solution temperature, the size and volume fraction of 尾 phase increase and the strength of the alloy decreases with the solution treatment in the (伪 尾) two-phase region. After aging, the 尾 matrix changes, and a large number of secondary 伪 phases are precipitated in the grain boundary and in the crystal. The size of the secondary 伪 phase has an important effect on the mechanical properties. With the increase of aging temperature, the secondary 伪 phase gradually coarsenes, which leads to the decrease of tensile strength. The solution temperature of Ti-5553 for aviation fasteners of 1240MPa should be below T 尾. Enough 尾 phase is left in the structure, so there are a large number of secondary 伪 phase precipitates in 尾 phase during aging, and the required high strength is obtained. At the same time, a certain amount of primary 伪 phase was retained in order to obtain good ductility. After heat treatment at 810 鈩，

本文编号：1904210