TB17钛合金等温时效析出行为

采用X射线衍射( XRD)、透射电子显微镜( TEM)、光学显微镜( OM)等对新型超高强韧 TB17钛合金次生α相转变动力学进行研究。实验结果表明,该合金经β相区固溶,520℃不同保温时间时效后,片层次生α相在β相基体上析出、形核、长大,并且与基体具有柏氏共格关系。短时时效后次生α相呈针状,随着保温时间延长,次生α相粗化呈短棒状。析出相含量对TB17钛合金强化具有重要影响,TB17钛合金在完全析出过程中,次生α相含量增加,时效硬化作用增加。 TB17钛合金次生α相等温相变动力学采用 JMAK方程进行描述。

Isothermal Aging Precipitate of TB17 Titanium Alloy

Transmission Electron Microscope ( TEM) , X-Ray Diffraction( XRD) and Optical Microscope( OM) were employed to inves-tigate the aging precipitation behavior of a new type of ultra-high strength TB17 titanium alloy. The results show that during heat solu-tion treated in theβphase field followed by aging the secondaryαphase is nucleated, precipitated and grew on theβphase matrix,and the precipitated phase is lamellar structure which has burgers relation with the matrix. The secondaryαphase content is increased rap-idly and finally reach a steady-state as aging time increased and the final product of aging consists ofαphase andβphase. there is a good linearity relationship between the content of secondary α phase and the hardness of age hardening. The TB17 titanium alloy iso-thermal phase transformation kinetics can be described by JMAK equation.