本文選題：高強鈦合金 + 緊固件��； 參考：《材料工程》2017年10期

【摘要】：采用掃描電鏡和透射電子顯微鏡研究不同熱處理制度對Ti-5553高強鈦合金顯微組織與力學性能的影響。結(jié)果表明:在(α+β)兩相區(qū)進行固溶處理時,隨著固溶溫度的升高,Ti-5553合金組織中的初生α相含量逐漸減少,β相的尺寸和體積分數(shù)均增加,合金強度逐漸降低。時效后β基體發(fā)生轉(zhuǎn)變,晶界和晶內(nèi)析出大量次生α相。次生α相的尺寸對力學性能產(chǎn)生重要影響,隨著時效溫度的升高,次生α相逐漸粗化,導致抗拉強度逐漸下降。1240MPa級航空緊固件用Ti-5553的固溶溫度應選擇Tβ以下,使組織中留有足夠的β相,從而時效時在β相中有大量次生α相析出,獲得需要的高強度。同時,保留一定含量的初生α相,以便獲得良好的塑韌性。經(jīng)810~820℃,1.5h,水淬+510℃,10h,空冷熱處理后,合金可以獲得較好的綜合性能,抗拉強度達1500MPa,伸長率達14.8%,斷面收縮率為38.6%。固溶和時效態(tài)的拉伸斷口均存在大量韌窩,材料具有良好的塑韌性。
[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 偽 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 (偽 尾) two-phase region. After aging, the 尾 matrix changes, and a large number of secondary 偽 phases are precipitated in the grain boundary and in the crystal. The size of the secondary 偽 phase has an important effect on the mechanical properties. With the increase of aging temperature, the secondary 偽 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 偽 phase precipitates in 尾 phase during aging, and the required high strength is obtained. At the same time, a certain amount of primary 偽 phase was retained in order to obtain good ductility. After heat treatment at 810 鈩，

本文編號：1904210