H. R. Ezatpour - Hakim Sabzevari University
Gholam Reza Ebrahimi - Materials and Metallurgical Engineering Department, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran
Fateme Zarghani - Department of Materials and Polymer Engineering, Hakim Sabzevari University, Sabzevar, Iran

The morphology of the α-phase in titanium alloys considerably affected their physical and mechanical properties. In this research, the effect of applied strain and inter-pass times on the morphology of the α-phase was studied in the two-step hot deformation process. Hot compression tests were performed at ۹۰۰ ºC and ۰.۰۰۱ s-۱ while the strains in the first and second passes were set as (first cycle: ۰.۶ and ۰.۳) and (second cycle: ۰.۳ and ۰.۶) respectively, with various inter-pass times. The work softening parameter obtained from the stress-strain curves showed that the proper time for globularization of α-layers for the first pass strain of ۰.۶ was ۲۴۰ s and for the second strain of ۰.۳ it was ۲۴۰ and ۳۰۰ s. Microstructure results indicated that the first pass strain of ۰.۳ and the inter-pass time of ۲۴۰ s were the optimum conditions for globularization of α layers.

Ti-۶Al-۴V alloy, Two-step hot deformation process, Microstructure