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采用X射线衍射仪(XRD)、金相显微镜(OM)、扫描电镜(SEM)、透射电子显微镜(TEM)和维氏硬度计,开展了新型超高强度TB17钛合金在β单相区固溶处理后,1~10℃·min~(-1)冷却速度对合金显微组织和显微硬度影响规律的研究。结果表明:TB17钛合金冷却过程中发生了β→α+β转变,当冷却速度为1和3℃·min~(-1)时,组织为典型的片层组织。当冷却速度增加到10℃·min~(-1)时,α相的析出量明显减少,沿着晶界析出大量相互平行的针状α相,晶内存在少量的相互交叉的针状α相。并且随着冷却速度从1℃·min~(-1)增加到10℃·min~(-1),α相析出量、α片层厚度、晶界α厚度均减小。其中,α相析出量由48%减少到5%,α片层平均厚度由0.7μm减小到0.05μm,晶界α平均厚度由1.9μm减小到0.5μm。冷却速度对TB17钛合金显微硬度具有重要影响,在1~5℃·min~(-1)冷却速度下,显微硬度随着冷却速度的增加逐渐升高;在5~10℃·min~(-1)冷却速度下,显微硬度随着冷却速度的增加逐渐降低。
A new ultra-high strength TB17 titanium alloy was dissolved in the β-phase region by XRD, OM, SEM, TEM and Vickers hardness tester After treatment, 1 ~ 10 ℃ · min ~ (-1) cooling rate on the microstructure and microhardness of the alloy. The results show that the transformation of β → α + β occurs during the cooling of TB17 titanium alloy, and the microstructure is typical lamella when the cooling rate is 1 and 3 ℃ · min ~ (-1). When the cooling rate was increased to 10 ℃ · min ~ (-1), the amount of α-phase precipitates decreased obviously. A large number of acicular α-phases precipitated along the grain boundary. A small amount of acicular α-phase . And as the cooling rate increased from 1 ℃ · min -1 to 10 ℃ · min -1, the amount of α phase precipitates, the thickness of α sheet and the grain boundary α all decreased. Among them, the amount of α phase precipitates decreased from 48% to 5%, the average thickness of α sheet decreased from 0.7μm to 0.05μm, and the average grain boundary α thickness decreased from 1.9μm to 0.5μm. The cooling rate has an important effect on the microhardness of TB17 titanium alloy. At the cooling rate of 1 ~ 5 ℃ · min ~ (-1), the microhardness gradually increases with the increase of cooling rate. At cooling rate of 5 ~ 10 ℃ · min ~ (-1) cooling rate, the microhardness decreases with the cooling rate increases.