Understanding the relationship between microstructure and mechanical properties in HIPped Ti-5Al-5Mo-5V-3Cr

T Technology > TL Motor vehicles. Aeronautics. Astronautics

Gao, Jianshu ; Bowen, Paul,Li, Hang Yue,Hao, Xinjiang

University:University of Birmingham

Department:School of Metallurgy and Materials

关键词: T Technology;    TL Motor vehicles. Aeronautics. Astronautics;   

Others  :  http://etheses.bham.ac.uk//id/eprint/8139/1/Gao18PhD.pdf

来源: University of Birmingham eTheses Repository

【 摘 要 】

Ti-5Al-5Mo-5V-3Cr (Ti-5553), a relatively new generation beta titanium alloy has the advantage of high strength. It is a current generation alloy used in landing gear. Currently, landing gear components are large scale and processed through forging, followed by complex heat treatments. HIPping (hot isostatic pressing) is an alternative way to process this alloy. In this project, work was carried out on investigating microstructures and mechanical properties of HIPped Ti-5553 alloy. During comparisons on fracture toughness of different types of specimens, specimens are first heat treated to a similar strength level. And fracture toughness values are calculated at the same strength level circumstance. Various microstructures are obtained through different heat treatments. Different microstructures can be achieved through specified treated temperature/ time and quenching methods. Results show that larger grain size and coarser intergranular lath-like grain boundary alpha can improve the fracture toughness. One shell-like microstructure is obtained through different heat treatment conditions. Mechanical test was carried out on this kind of microstructure and compared to normal beta annealed microstructures. To investigate the influence of microstructure on fracture toughness, techniques including optical microscope (OM), scanning electron microscope (SEM), and confocal laser scanning microscope have been used.