On the effect of incremental forming on alpha phase precipitation and mechanical behavior of beta-Ti-10V-2Fe-3Al

18th Chemnitz Seminar on Materials Engineering – 18. Werkstofftechnisches Kolloquium

Winter, S.^1 ; Wagner, M.F.-X.^1

Department of Materials Science, Institute of Materials Science and Engineering, Tech-nische Universität Chemnitz, Chemnitz

09125, Germany^1

关键词: Conventional annealing;    Future applications;    Incremental forming;    Lamellar precipitates;    Mechanical behavior;    Microstructural parameters;    Microstructure and mechanical properties;    Thermo-mechanical processing;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/118/1/012026/pdf
DOI  :  10.1088/1757-899X/118/1/012026

来源: IOP

【 摘 要 】

A combination of good ductility and fatigue resistance makes β-titanium alloys interesting for many current and potential future applications. The mechanical behavior is primarily determined by microstructural parameters like (beta phase) grain size, morphology and volume fraction of primary / secondary α-phase precipitates, and this allows changing and optimizing their mechanical properties across a wide range. In this study, we investigate the possibility to modify the microstructure of the high-strength beta titanium alloy Ti-10V-2Fe-3Al, with a special focus on shape and volume fraction of primary α-phase. In addition to the conventional strategy for precipitation of primary α, a special thermo-mechanical processing is performed; this processing route combines the conventional heat treatment with incremental forming during the primary α-phase annealing. After incremental forming, considerable variations in terms of microstructure and mechanical properties can be obtained for different thermo-mechanical processing routes. The microstructures of the deformed samples are characterized by globular as well as lamellar (bimodal) α precipitates, whereas conventional annealing only results in the formation of lamellar precipitates. Because of the smaller size, and the lower amount, of α-phase after incremental forming, tensile strength is not as high as after the conventional strategy. However, high amounts of grain boundary α and lamellar αp-phase in the undeformed samples lead to a significantly lower ductility in comparison to the matrix with bimodal structures obtained by thermo-mechanical processing. These results illustrate the potential of incremental forming during the annealing to modify the microstructure of the beta titanium Ti-10V-2Fe-3Al in a wide range of volume fractions and morphologies of the primary α phase, which in turn leads to considerably changes, and improved, mechanical properties.