Ti-Fe-Ni-Al 계 합금의 초소성 특성에 미치는 합금원소의 영향 = Alloying Effects on the Superplastic Behavior

다국어 초록 (Multilingual Abstract)

The aim of the present investigation was to develop a new titanium alloy with improved superplastic performance (higher elongation and lower forming temperature) through alloying with Fe, Ni and Al. A total of nine alloy compositions were used in which Fe content was fixed while Ni and A1 contents were varied. The alloy Ti-5Fe-4Al-2Ni was proved to be promising in that it gives a large elongation over 1500% at a low deformation temperature of 650℃, which was made possible mainly due to the existence of Fe and Ni. Alloying with Ni within suitable amount was found to increase the strain rate sensitivity and to decrease the flow stress, while the effect of Al addition was found to be insignificant to the superplastic behavior but its content should be limited. Possible mechanisms and optimum volume fractions for the superplasticity in the present alloy system were also discussed.