Microstructure, mechanical properties and fracture mechanism of TC32 titanium alloy with different heat treatment processes

doi:10.13251/j.issn.0254-6051.2021.04.019

Abstract

Abstract: Effect of two heat treatment processes, which were normal annealed (700 ℃ for 2 h, AC) and double annealed (880 ℃ for 2 h, AC and 550 ℃ for 6 h, AC), on microstructure and mechanical properties of the new high-performance and low-cost TC32 titanium alloy was studied by using optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM), and tensile testing machine. The results show that after normal annealing, the content of primary α phase is about 37.2%, and a slight spheroidization occurres, the β-transformed matrix is composed of coarser lamellar secondary α phase and residual β phase. The average ultimate strength (UTS) under this process is 939 MPa, and the average elongation (EL) is 17.4%. After double annealing, volume fraction of primary α phase which occurred recrystallization is about 11.8%, and β-transformed matrix is composed of fine lamellar secondary α phase with weaving basket-weave structures. The average ultimate strength (UTS) under this process is 1258 MPa, and the average elongation (EL) is 9.4%. Fracture morphologies show that the tensile fracture mechanism of both processes belongs to ductile fracture. The fracture characteristics of normal annealed have larger fibrous and shear lip zones, no obvious radical zone, and more equiaxed dimples with larger in size and deeper in depth. The fracture characteristics of double annealed have a certain area of radical zone, in addition to the equiaxed dimples, a number of tearing edges is observed.

Key words: TC32 titanium alloy, heat treatment, microstructure, mechanical properties, fracture mechanism

CLC Number:

TG146

Li Mingbing, Wang Xinnan, Shang Guoqiang, Zhu Liwei, Li Jing, Li Xing, Zhu Zhishou. Microstructure, mechanical properties and fracture mechanism of TC32 titanium alloy with different heat treatment processes[J]. Heat Treatment of Metals, 2021, 46(4): 112-117.

References

[1] Gerd Lütjering,James C Williams.Titanium[M].New York:Springer,C2007.
[2] GB/T 6611—2008,钛及钛合金术语和金相图谱[S].
[3] 魏寿庸,何瑜,祝瀑.世界各国工业钛合金的成分、相组成与性能特征[C]//第十四届中国有色金属学会材料科学与工程合金加工学术研讨会文集.2011:367-374.
Wei Shouyong,He Yu,Zhu Pu.The characteristic properties,composition and phase structure of world commercial titanium alloys[C]//Proceedings of the 14th China Society of Nonferrous Metals Symposium on Materials Science and Engineering Alloy Processing.2011:367-374.
[4] 曹春晓.我国航空用钛合金面临的21世纪的挑战[J].钛工业进展,1999(5):1-5.
Cao Chunxiao.Challenges of Chinese aviation titanium alloy in the 21st century[J].Titanium Industry Progress,1999(5):1-5.
[5] Williams J C.Alternate materials choices—some challenges to the increased use of Ti alloys[J].Materials Science and Engineering,1999,263(2):107-111.
[6] 朱知寿,商国强,王新南,等.低成本高性能钛合金研究进展[J].钛工业进展,2012,29(6):1-5.
Zhu Zhishou,Shang Guoqiang,Wang Xinnan,et al.Research and development of low cost and high performance titanium alloys[J].Titanium Industry Progress,2012,29(16):1-5.
[7] 朱知寿,王新南,商国强,等.新型高性能钛合金研究与应用[J].航空材料学报,2016,36(3):7-12.
Zhu Zhishou,Wang Xinnan,Shang Guoqiang,et al.Research and application of new type of high performance titanium alloy[J].Journal of Aeronautical Materials,2016,36(3):7-12.
[8] 王新南,费跃,刘洲,等.航空用新型低成本钛合金显微组织与损伤容限性能关系研究[J].钛工业进展,2013,30(2):7-10.
Wang Xinnan,Fei Yue,Liu Zhou,et al.Research of the relationship between microstructure and damage-tolerance property of new low cost titanium alloy in aviation application[J].Titanium Industry Progress,2013,30(2):7-10.
[9] 费跃,朱知寿,王新南,等.锻造工艺对新型低成本钛合金组织和性能影响[J].稀有金属,2013,37(2):186-191.
Fei Yue,Zhu Zhishou,Wang Xinnan,et al.Influence of forging process on microstructure and mechanical properties of a new low-cost titanium alloy[J].Chinese Journal of Rare Metals,2013,37(2):186-191.
[10] 李明兵,朱知寿,王新南,等.显微组织对TC32钛合金高周疲劳性能的影响关系研究[J].中国有色金属学报,2016,26(9):1886-1892.
Li Mingbing,Zhu Zhishou,Wang Xinnan,et al.The influence of microstructure on high cycle fatigue properties of TC32 titanium alloy[J].Transactions of Nonferrous Metals Society of China,2016,26(9):1886-1892.
[11] Stefansson N,Semiatin S L.Mechanisms of globularization of Ti-6Al-4V during static heat treatment[J].Metallurgical and Materials Transaction A,2003,34(3):691-698.
[12] 鲍学淳,程礼,陈煊,等.热处理工艺对 TC4 钛合金组织和力学性能的影响[J].金属热处理,2019,44(6):137-140.
Bao Xuechun,Cheng Li,Cheng Xuan,et al.Effect of heat treatment process on microstructure and mechanical properties of TC4 titanium alloy[J].Heat Treatment of Metals,2019,44(6):137-140.
[13] 鲁媛媛,马保飞,刘源仁.固溶处理温度对 TC4 钛合金组织和性能的影响[J].金属热处理,2019,44(6):153-158.
Lu Yuanyuan,Ma Baofei,Liu Yuanren.Effect of solution treatment temperature on microstructure and properties of TC4 titanium alloy[J].Heat Treatment of Metals,2019,44(6):153-158.
[14] 鲁媛媛,马保飞,刘源仁.时效处理对 TC4 钛合金微观组织和力学性能的影响[J].金属热处理,2019,44(7):34-38.
Lu Yuanyuan,Ma Baofei,Liu Yuanren.Influence of aging treatment on microstructure and mechanical properties of TC4 titanium alloy[J].Heat Treatment of Metals,2019,44(7):34-38.
[15] 王新南,朱知寿,商国强,等.热处理工艺对Ti-6Al-4V ELI合金厚截面锻件力学性能的影响[J].钛工业进展,2019,36(2):29-33.
Wang Xinnan,Zhu Zhishou,Shang Guoqiang,et al.Effect of heat treatment process on mechanical properties of Ti-6Al-4V ELI alloy thick section forgings[J].Titanium Industry Process,2019,36(2):29-33.
[16] 朱知寿,商国强,王新南,等.航空用钛合金显微组织控制和力学性能关系[J].航空材料学报,2020,40(3):1-10.
Zhu Zhishou,Shang Guoqiang,Wang Xinnan,et al.Microstructure controlling technology and mechanical properties relationship of titanium alloys for aviation applications[J].Journal of Aeronautical Materials,2020,40(3):1-10.
[17] Barriobero-Vila P,Requena G,Buslaps T,et al.Role of element partitioning on the α-β phase transformation kinetics of a bi-modal Ti-6Al-6V-2Sn alloy during continuous heating[J].Journal of Alloy and Compounds,2015,626:330-339.
[18] Zeng L R,Chen H L,Li X,et al.Influence of alloy element partitioning on strength of primary α phase in Ti-6Al-4V alloy[J].Journal of Materials Science and Technology,2018,34(5):782-787.
[19] 黄森森,马英杰,张仕林,等.α+β两相钛合金元素再分配行为及其对显微组织和力学性能的影响[J].金属学报,2019,55(6):741-750.
Huang Sensen,Ma Yinjie,Zhang Shilin,et al.Influence of alloying elements partitioning behaviors on the microstructure and mechanical properties in α+β titanium alloy[J].Acta Metallurgica Sinica,2019,55(6):741-750.