Journal of the KIMST, Vol. 20, No. 2, pp. 206-216, 2017 ISSN 1598-9127 DOI http://dx.doi.org/10.9766/KIMST.2017.20.2.206 206 / 한사학기술학회지 제20 제2호(2017년 4) 1. 서 론 티타늄 합금 높 비강도와 수한 내식성, 온 * Corresponding author, E-mail: songos@cnu.ac.kr Copyright ⓒ The Korea Institute of Military Science and Technology 및 저온에서 수한 기적 성질 등로 하여 전 투기, 도탄, 전투차량 등 방분야에 적용 지속 증가하 다 [1] . 티타늄 합금(주로 Ti-6Al-4V) 또한 수한 속 충돌 저항성(방탄성능) 갖는데, 티타늄 합금 적용할 , 동에너지탄에 대해 조 중량 철강 또는 알루미늄 갑판재와 비해서 Research Paper 소재 ․ 나노 ․ 공정 부문 Ti-6Al-4V 합금의 동적 변형 거동에 관한 연구 서용석 1) ․ 이영신 2) ․ 송오섭 *,2) 1) 국방과학연구소 제5기술연구본부 2) 충남대학교 기계공학부 A Study on the Dynamic Behavior of Ti-6Al-4V Alloy Yongseok Seo 1) ․ Young-Shin Lee 2) ․ Ohseop Song *,2) 1) The 5th Research and Development Institute, Agency for Defense Development, Korea 2) Department of Mechanical Engineering, Chungnam National University, Korea (Received 23 September 2016 / Revised 13 October 2016 / Accepted 10 February 2017) ABSTRACT This paper studies on the dynamic properties of Ti-6Al-4V alloy. After forming the four different micro structures(equiaxed, lamellar, and 2 bimodals) through heat treatments, static and dynamic properties of each structure were investigated quantitatively. Dynamic behaviors of the alloy are observed by the compressive split Hopkinson pressure bar(SHPB) tests. In additon, parameters of Johnson-Cook equation were determined from the SHPB test results. In order to verify the suitability of the parameters, high velocity impact tests were performed and the results were compared with the numerical analysis results. Although the flow stress and the fracture strain of the bimodal structures were higher than those of the equiaxed structure at the static tests, the superior dynamic properties were observed at the equiaxed structure due to the effects of higher maximum flow stress and fracture strain. From the numerical analysis, J-C parameters which are determined on this study describe well the dynamic behavior of Ti-6Al-4V alloy. Experimental and analysis results are consistent with ± 5 % of an average error. Key Words : Ti-6Al-4V(티타늄 64 합금), Dynamic Behavior(동적거동), Compressive Split Hopkinson Pressure Bar Test (압축 홉킨슨 봉 실험), High Velocity Impact Test(속 충돌실험), Johnson-Cook Equation(존슨-쿡 방정식)