【摘要】 对TB17钛合金进行了亚β固溶处理(固溶温度800～835℃,固溶时间0.5～9 h),采用电子探针分析了Al、Mo、Nb元素在初生α相和β基体中的分布,研究了亚β固溶对合金初生α相析出、元素重分布规律及时效次生α相的影响。结果表明,合金在亚β温度固溶时晶内析出以针状初生α相为主,晶界析出以片层状初生α相为主。初生α相析出量随亚β固溶温度升高而降低,固溶温度高于825℃时基本不析出α相。初生α相尺寸随固溶时间延长而增大,固溶温度815℃时固溶时间超过2 h后,初生α相析出量达到稳态。Al元素倾向于在初生α相中富集,Mo和Nb元素则倾向于β基体富集。初生α相中心部位Al元素浓度较高,边缘部位较低,而Mo和Nb元素中心部位则浓度较低,边缘部位较高。增加初生α相析出量,会使β基体Al浓度降低,Mo、Nb元素浓度升高。初生α相较少(2%)时初生α相周围的次生α相以针状或片层状形貌为主,远离初生α相区域的次生α相以似网篮结构为主,初生α相较多(10%)时次生α相均以片层状形貌为主。更多还原

【Abstract】 Subcritical β solution treatment of TB17 titanium alloy was carried out at the solution temperature range from 800 ℃ to 835 ℃ and the solution time range from 0.5 h to 9 h, and the distribution of Al, Mo and Nb elements in the primary α phase, element partitioning and β matrix was studied by electron probe microanalysis(EPMA). Effect of subcritical β solution on precipitation of primary α phase and secondary α phase of the alloy was investigated. The experimental results show that primary α phase presents two typical morphologies of needle-type and lamellae-type structure, which the needle-type α phase is distributed at grain interior and lamellae-type α phase is distributed at grain boundaries. The amount of primary α phase decreases with the increasing of solution temperature. No primary α phase is observed at the solution temperature higher than 825 ℃. The amount of primary α phase increases with the decreasing of solution temperature. The precipitation of primary α phase will reach a steady state at the temperature of 815 ℃ and the solution time higher than 2 h. Al element tends to be enriched in the primary α phase, and Mo and Nb elements tend to be enriched in the β matrix. The Al concentration in the center of the α phase is higher than that in the edge, while the Mo and Nb concentration in the center is lower than that in the edge. Increasing the amount of primary α phase will decrease Al concentration and increase Mo and Nb concentration in the β matrix.When the amount of primary α phase is low, the secondary α phase near primary α phase presents the morphologies of needle-type or lamellae-type structure, and morphology of the basketweave structure for the secondary α phase far from primary α phase. When the amount of primary α phase is high, the secondary α phase presents the morphologies of needle-type or lamellae-type structure.更多还原