The advance in the plastic forming theory and technology of titanium alloys

The objective of this paper is to introduce recent studies of my research group in regard to advance plastic forming theory and technology of titanium alloys. In my research group, the deformation behavior and the microstructure evolution of titanium alloys are in depth investigated in high temperature deformation. New microstructure model and constitutive relationship of titanium alloys are developed based on internal state variable method. The novelty theory of processing maps is proposed using the microstructure-based viscoplastic constitutive relationship, the law of classical thermodynamic and Ziegler's continuum principles. Those models are applied to the hot forming of titanium alloys so as to optimize the processing parameters and realize the precision and the net shape manufacturing process with reduced costs and short cycle. Moreover, advance plastic forming technology, including thermohydrogen processing(THP)and equal channel angular pressing(ECAP)are applied to titanium alloys in order to refine microstructure and improve mechanical properties.