Ti6Al4V alloy is widely used as a system material in high temperature and high pressure environments in various industrial fields and is difficult to mechanically machine. Thus, high temperature processing methods such as hot forging, rolling, and hot forming are usually applied. Among various methods for deriving optimal molding conditions during high-temperature processing, the dynamic material model suggests energy dissipation efficiency according to the flow stress of the material. However, the energy dissipation efficiency merely numerically represents the change in flow stress, not the metallurgical behavior of the material. Therefore, it is necessary to understand the difference in energy dissipation efficiency in relation to the high-temperature deformation mechanism. In this study, high temperature compression tests were performed on the Ti6Al4V alloy. The temperature range was set at 800°C³1200°C at intervals of 50°C, and the strain rate was set at 1 © 10 0 /sec³1 © 10 ¹3 /sec at intervals of 10 ¹1 /sec. Based on the results of the experiments, flow stress and processing maps were derived, and the high temperature plastic deformation behaviors of Ti6Al4V alloy were analyzed in correlation with the microstructural changes and mechanical properties according to temperature and strain rate. And the prior beta grain size according to the difference in energy dissipation efficiency was explained for each condition.

Ti-6Al-4V alloys are used in various industrial fields such as aircraft parts due to its excellent specific strength and mechanical properties. A high-temperature forming technology has been applied because it is difficult to process complex shapes. During the high-temperature forming process, the microstructure changes significantly due to temperature, strain rate, reduction ratio, and other process variables, and mechanical properties of high-temperature molded products are changed accordingly. Therefore, in this study, a high-temperature compression test was performed on AMS4928, which is one of Ti-6Al-4V alloys used as a material for aircraft parts, and the severe plastic deformation and dead zone were confirmed in connection with the processing map. The changes in microstructure were comparatively analyzed. In addition, it was confirmed that there was a difference in formability due to grain refinement by dynamic recrystallization, and optimal high-temperature forming conditions were derived by linking and analyzing the formability and microstructural factors.

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