In this study, we have prepared a Ti-6Al-4V/V/17-4 PH composite structure via a direct energy deposition process, and analyzed the interfaces using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The joint interfaces comprise two zones, one being a mixed zone in which V and 17-4PH are partially mixed and another being a fusion zone in the 17-4PH region which consists of Fe+FeV. It is observed that the power of the laser used in the deposition process affects the thickness of the mixed zone. When a 210 W laser is used, the thickness of the mixed zone is wider than that obtained using a 150 W laser, and the interface resembles a serrated shape. Moreover, irrespective of the laser power used, the expected  phase is found to be absent in the V/17-4 PH stainless steel joint; however, many VN precipitates are observed.

Abstract
1. 서 론
2. 실험방법
3. 결과 및 고찰
    3.1. V//17-4PH 접합계면 부위 SEM 관찰
    3.2. V//17-4PH 접합계면 부위 TEM 관찰(DB210)
    3.3. V//17-4PH 접합계면 부위 TEM 관찰(DB150)
4. 고 찰
5. 결 론
References

• 이세환(국방과학연구소) | Se-Hwan Lee (Agency for Defense Development, Republic of Korea)
• 김호범(국립한밭대학교 신소재공학과) | Hobeom Kim (Department of Materials Science & Engineering, Hanbat National University, Republic of Korea)
• 김정한(국립한밭대학교 신소재공학과) | Jeoung Han Kim (Department of Materials Science & Engineering, Hanbat National University, Republic of Korea) Corresponding author