Additively manufactured metallic components contain high surface roughness values, which lead to unsatisfactory high cycle fatigue resistance. In this study, high cycle fatigue properties of selective laser melted Ti-6Al- 4V alloy are investigated and the effect of dry-electropolishing, which does not cause weight loss, on the fatigue resistance is also examined. To reduce the internal defect in the as-built Ti-6Al-4V, first, hot isostatic pressing (HIP) is conducted. Then, to improve the mechanical properties, solution treatment and aging are also implemented. Selective laser melting (SLM)-built Ti64 shows a primary α and secondary α+β lamellar structure. The sizes of secondary α and β are approximately 2 μm and 100 nm, respectively. On the other hand, surface roughness Ra values of before and after dry-electropolishing are 6.21 μm and 3.15 μm, respectively. This means that dry-electropolishing is effective in decreasing the surface roughness of selective laser melted Ti-6Al-4V alloy. The comparison of high cycle fatigue properties between before and after dry-electropolished samples shows that reduced surface roughness improves the fatigue limit from 150 MPa to 170 MPa. Correlations between surface roughness and high cycle fatigue properties are also discussed based on these findings.

Abstract
1.서 론
2. 실험 방법
3. 결과 및 고찰
4. 결 론
References

• 양동훈(인하대학교 신소재공학과) | Dong-Hoon Yang (Department of Materials Science and Engineering, Inha University)
• 김영균(인하대학교 신소재공학과) | Young-Kyun Kim (Department of Materials Science and Engineering, Inha University)
• 황유진(인하대학교 신소재공학과) | Yujin Hwang (Department of Materials Science and Engineering, Inha University)
• 김명세(㈜아우라테크) | Myoung-Se Kim (Auratech Co.)
• 이기안(인하대학교 신소재공학과) | Kee-Ahn Lee (Department of Materials Science and Engineering, Inha University) Corresponding Author