【摘要】 用金相法和x射线衍射法研究了一种在室温亚稳β型的钛合金。合金中除钛外主要含有约5%Mo,5%V,8%Cr和3%Al。样品在900℃固溶处理后冰水淬到室温,以及继续冷到液氦温度4.2K都只有β相存在。这说明本研究所用钛合金（以下简称TB₂）的马氏体点（Ms）低于4.2K。TB₂合金自β单相区淬火到室温没有见到ω相,这说明此合金或者不生成变温ω相,或者生成的ω相不能稳定到室温。透射电子显微镜研究证明了TB2合金在300℃时效50小时后析出大量恒温ω相,在样品的局部区域观察到溶质元素贫化的β′相。更多还原

【Abstract】 The formation of isothermal to phase during tempering in a quenched meta- stable β titanium alloy (TB2) was investigated with metallographical, electron and X ray diffraction methods. This alloy contains about 5wt%Mo, 5wt%V, 8wt%Cr and 3wt%Al. Samples are solution treated at 900℃ and then quenched in ice-water. After quenched to liquid he1ium, microstructure and crystalline lattice observed at the room temperature are β phase only. This feature shows that martensitic temperature Ms is lower than 4. 2°K. Transmi- ssion electron microscopic study shows that many isothermal ω grains are pre- cipitated from the β metastable solid solution of TB2 alloy after tempering at 330℃ for 50hrs. The number of ω crystallites increase with the tempering time, but the sizes of the crystallites do not increase severely. The reason of this phenomenon is the formation characteristics of the ω phase, i. e. if is easy to displacively nucleate but growth with difficulty due to the high strain induced by the new phase The β’ phase, which is lean of alloying ele- ments, was observed in local regions. For calculating the martensitic temper- ature of TB2 alloy, the rule of simple addition for alloying elements effects was used. The calculated result agrees very well with the experimental finding. TB2 is a useful new titanium alloy.更多还原