TC25G钛合金高温变形组织演变及强塑性研究  

Microstructure Evolution and Mechanical Property of TC25G Titanium Alloy During High Temperature Deformation

作　　者：张晓园[1,2,3,4] 刘向宏 杜予晅[1,2,3] 李付国 王凯旋[1,2,3] 李少强 杨恬[1,2,3] Zhang Xiaoyuan;Liu Xianghong;Du Yuxuan;Li Fuguo;Wang Kaixuan;Li Shaoqiang;Yang Tian(Western Superconducting Technologies Co.,Ltd,Xi’an 710018,China;National&Local Joint Engineering Laboratory for Special Titanium Alloy Processing Technologies,Xi’an 710018,China;Xi’an Key Laboratory of Special Titanium Alloy Processing and Simulation Technologies,Xi’an 710018,China;Northwestern Polytechnical University,Xi’an 710072,China)

机构地区：[1]西部超导材料科技股份有限公司,陕西西安710018 [2]特种钛合金制备技术国家地方联合实验室,陕西西安710018 [3]西安市特种钛合金制备及仿真技术重点实验室,陕西西安710018 [4]西北工业大学,陕西西安710072

出　　处：《稀有金属材料与工程》2023年第12期4227-4237,共11页Rare Metal Materials and Engineering

摘　　要：对比研究了网篮组织TC25G钛合金棒材在不同变形量下的组织演变及其550℃热暴露和蠕变性能变化。结果表明:随变形量的增加,合金热暴露后拉伸塑性逐渐增加,而高温抗蠕变性逐渐减弱,2种性能在变形量100%时达到良好匹配,均可满足工程应用要求。变形量的增加对应显微组织中片层α相的球化过程,在片层α相充分球化前,显微组织中多层级结构的界面强化效应使得合金具有良好的高温抗蠕变性;而α相充分球化后,以等轴组织为主的显微组织使得合金具有较好的塑性。随变形量的增加,热暴露后拉伸断口韧窝尺寸逐渐变得细小均匀,且韧窝深度增加,表明合金热暴露后塑性提升。纳米显微硬度测试结果表明,合金中初生α相的显微硬度高于β转变组织,通过固溶温度调整合金中α相的含量和分布,可提升抗蠕变性,但其效果不及变形量的调控显著;为获得最佳的高温强塑性匹配,可通过控制片层α相球化程度来实现。Microstructure evolution of TC25G titanium alloy bar with basket microstructure after different deformation degrees was studied and the changes of its thermal stability and creep resistance at 550°C were compared.The results show that the tensile plasticity after thermal exposure increases and the creep resistance decreases with the increase in deformation degree.The plasticity and creep resistance match well at 100%deformation degree and can meet the requirements of engineering application.The increase in deformation degree corresponds to the spheroidizing process of lamellarαphase.Before the lamellarαphase is fully spheroidized,the interface strengthening effect of multi-layer structure makes the alloy have good creep resistance at high temperature.However,afterα-phase spheroidization,the alloy has better plasticity because of the microstructure dominated by equiaxed microstructure.With the increase in deformation degree,the size of the fracture dimples becomes smaller and more uniform,and the dimple depth increases,which indicates that the plasticity after thermal exposure increases.The results of nano-hardness test show that the microhardness of primaryαphase is higher than that ofβtransforms,and the creep resistance can be improved by adjusting the content and distribution ofαphase in the alloy by solution temperature.The extent of lamellarαphase spheroidization can be controlled to obtain the best matching of strength and plasticity at high temperature.

关 键 词：TC25G钛合金 组织演变 热稳定性 抗蠕变性 

分 类 号：TG146.23[一般工业技术—材料科学与工程]