Microstructure evolution during warm working of Ti-6Al-4V with a colony-alpha microstructure

A high-resolution electron backscatter diffraction technique was employed to investigate microstructure evolution during warm working of Ti-6Al-4V with a colony-alpha. microstructure. Particular emphasis was paid to the specific mechanisms governing this process. Microstructure development was found to be driven mainly by the geometrical requirements of the imposed strain and by the kinking of alpha lamellae. For the most part, the lamellar microstructure was surprisingly stable during straining, with limited globularization observed only in kinked alpha colonies. The kinking process was shown to be closely linked with the development of shear bands within the colonies. These observations Suggest that changes in strain path may be beneficial in promoting globularization during warm working. (C) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.