An irradiation hardening of Inconel 718 produced by selective laser melting (SLM) was studied based on the microstructural observation and mechanical behavior. Ion irradiation for emulating neutron irradiation has been proposed owing to advantages such as low radiation emission and short experimental periods. To prevent softening caused by the dissolution of ' and '' precipitates due to irradiation, only solution annealing (SA) was performed. SLM SA Inconel 718 specimen was ion irradiated to demonstrate the difference in microstructure and mechanical properties between the irradiated and non-irradiated specimens. After exposing specimens to Fe3+ ions irradiation up to 100 dpa (displacement per atom) at an ambient temperature, the hardness of irradiated specimens was measured by nanoindentation as a function of depth. The depth distribution profile of Fe3+ and dpa were calculated by the Monte Carlo SRIM (Stopping and Range of Ions in Matter)-2013 code under the assumption of the displacement threshold energy of 40 eV. A transmission electron microscope was utilized to observe the formation of irradiation defects such as dislocation loops. This study reveals that the Frank partial dislocation loops induce irradiation hardening of SLM SA Inconel 718 specimens.

1. Introduction
2. Experimental
    2.1. 사용 재료 및 적층 제조 공정 변수
    2.2. 이온 조사 실험 조건 및 미세조직 평가 방법
    2.3. 나노압입시험
3. Results and Discussion
    3.1. 이온 조사로 인한 경도 변화 나노압입시험 결과
    3.2. 이온 조사 후 미세조직 분석 결과
4. Conclusion
Acknowledgement

• 서주원(서울대학교 공과대학 재료공학부, 한국원자력연구원 재료안전기술연구부) | Joowon Suh (Department of Materials Science and Engineering & Research Institute of Advanced Materials, Seoul National University, Seoul 08826, Republic of Korea, Materials Safety Technology Development Division, Korea Atomic Energy Research Institute, Daejeon 34057, Republic of Korea)
• 임상엽(한국원자력연구원 재료안전기술연구부) | Sangyeob Lim (Materials Safety Technology Development Division, Korea Atomic Energy Research Institute, Daejeon 34057, Republic of Korea)
• 진형하(한국원자력연구원 재료안전기술연구부) | Hyung-Ha Jin (Materials Safety Technology Development Division, Korea Atomic Energy Research Institute, Daejeon 34057, Republic of Korea)
• 천영범(한국원자력연구원 재료안전기술연구부) | Young-Bum Chun (Materials Safety Technology Development Division, Korea Atomic Energy Research Institute, Daejeon 34057, Republic of Korea)
• 강석훈(한국원자력연구원 재료안전기술연구부) | Suk Hoon Kang (Materials Safety Technology Development Division, Korea Atomic Energy Research Institute, Daejeon 34057, Republic of Korea) Corresponding Author
• 한흥남(서울대학교 공과대학 재료공학부) | Heung Nam Han (Department of Materials Science and Engineering & Research Institute of Advanced Materials, Seoul National University, Seoul 08826, Republic of Korea)