Study on Globularization Behaviors of Pre-deformed TA15 alloy Subjected to Electric Pulse Treatment

Abstract:

Electric pulse treatment experiments were carried out on lamellar structure TA15 alloy subsequent to uniaxial compression deformation. Then, the morphologies of lamellar structure, dislocation structure and interfacial structure were characterized, and the microstructure evolution mechanisms of pre-deformed TA15 alloy with lamellar structure under the action of electric pulses were analyzed in depth. Results show that electric pulse promotes the atom diffusion and defect reactions in TA15 alloy, and introduces the mechanisms of boundary migration, termination migration and Ostwald ripening, indicating the occurrence of electricity-induced static globularization. With the increase of electric current density and energization time, the globularization rate of lamellar structure increases and the average grain size of α lamella first increases then decreases. Interlamellar shearing is regarded as the main globularization mechanism for the α lamella with severe strain localization, while boundary splitting is found to be the main globularization mechanism for the β matrix with relatively smaller deformation. The additional interfacial strengthening brought by the globularized α phase leads to a maximum micro-hardness improvement of 26.41%.

Key words:Electric pulse treatment; TA15 alloy; pre-deformation; lamellar globularization