| || Isothermal and Near-isothermal Processing of Titanium Alloys (Review Paper)
Author : Raghu, T.;Balasundar, I.;Rao, Sudhakara M.
Source : Defence Science Journal ; Vol:61(1) ; 2011 ; pp 72-80
Subject : 669 Metallurgy
Keywords : Isothermal processing;Near-isothermal processing;Titanium alloys;Aeroengine components;Metal-forming techniques;Superplastic materials;Structural materials
Abstract : Isothermal and near isothermal forging are specialised metal-forming techniques used for producing critical aeroengine components from advanced materials such as titanium alloys. The process is used to produce net/ near-net shape components, leading to optimum utilisation of materials. As titanium alloys are highly sensitive to temperature and strain rate, these processes help to deform these under slow and controlled strain rates. Further, these processes can be combined with other conventional and non-conventional metal-forming processes to refine the microstructure. For example, multi-axial isothermal forging coupled with pack rolling can be used to produce thin sheets out of titanium alloys with sub-micron grain size. The refined structure exhibits superplastic characteristics at low temperatures and high strain rates. This lower temperature superplastic characteristic can be exploited to establish technologies for producing various components. The paper highlights the capabilities of isothermal forging process and its variants.