双态组织TA19钛合金高温变形过程中的微观组织演变机制  

Microstructure evolution mechanism of TA19 titanium alloy with bi-modal structure during high temperature deformation

作　　者：李宏辉 王柯[1] 辛仁龙[1] 刘庆[1] LI Hong-hui;WANG Ke;XIN Ren-long;LIU Qing(School of Materials Science and Engineering,Chongqing University,Chongqing 400044,China)

机构地区：[1]重庆大学材料科学与工程学院,重庆400044

出　　处：《材料热处理学报》2020年第8期27-34,共8页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金(51971046)。

摘　　要：对具有双态组织的TA19钛合金进行热模拟压缩实验,采用扫描电镜、透射电镜和电子背散射衍射研究了合金变形后的微观组织,并研究了变形温度对合金等轴α相和片层α相演变的影响行为及其机制。结果表明:变形温度对合金的相含量、晶粒形貌、晶界取向差角、以及动态回复和动态再结晶行为都构成显著影响。变形温度较低时(820~860℃),片层α相比等轴α相的塑性变形量大,片层α相向弯曲状形貌转变,且内部发生了明显的动态回复和动态再结晶。变形温度较高时(900~940℃),片层α相在β相中重新析出,表现出平行排布的规则形貌,且晶界取向差角分布图在10°、60°和90°处出现明显的峰值。同时,较高的变形温度促进了等轴α相中的动态再结晶,从而使得大角度晶界增加,而位错密度降低。The thermal simulation compression experiments of TA19 titanium alloy with bi-modal microstructure were carried out,and microstructure of the alloy after deformation was studied by means of scanning electron microscopy,transmission electron microscopy and electron back scattering diffraction technique.The effect of deformation temperature on the evolution of the equiaxedαphase and lamellarαphase of the alloy and its mechanism were also investigated.The results show that the deformation temperature has significant influence on the phase content,grain morphology,grain boundary misorientation angle,dynamic recovery and dynamic recrystallization behavior of the alloy.When the deformation temperature is low(820-860℃),the lamellarαhas a large amount of plastic deformation compared with the equiaxedαphase,and the lamellarαphase changes to the curved shape morphology,and obvious dynamic recovery and dynamic recrystallization occur.When the deformation temperature is high(900-940℃),the lamellarαphase is re-precipitated in theβphase,showing the regular morphology of parallel arrangement,and the grain boundary misorientation angle distribution map shows obvious peaks at 10°,60°and 90°.Meanwhile,the higher deformation temperature promotes the dynamic recrystallization in the equiaxedαphase,which makes the large angle grain boundary increase while the dislocation density decreases.

关 键 词：钛合金 双态组织 动态再结晶 相变 

分 类 号：TG146.2[一般工业技术—材料科学与工程]