DED와 L-PBF 공정으로 제조된 Ti-6Al-4V 적층재의 피로균열전파 거동

다국어 초록 (Multilingual Abstract)

Fatigue crack propagation(FCP) behavior of Ti-6Al-4V(Ti64) specimens fabricated by directed energy deposition(DED) and laser-powder bed fusion(L-PBF) processes with different annealing conditions and crack direction(CD) were studied. DED and L-PBF specimens resulted in reduced reversibility of growth cracks due to microstructure refinement, and as a result, FCP resistance was inferior to that of conventionally manufactured(CM) Ti64 specimens. It was found that the effect on the CD had no effect on the FCP behavior of the DED and L-PBF specimens. In the microscopic and fracture analysis of the specimens, no anisotropy of FCP was found for both DED and L-PBF Ti64 specimens. The main reason is that the phase boundary of randomly oriented acicular a platelets interfere microcrack growth.

목차 (Table of Contents)

• Table contents iii
• Figure contents iv
• Abstract vi
• I. 서론 1
• II. 이론적 배경 4
• 2.1 Ti64 합금 4
• 2.1.1 Ti64 합금의 미세조직과 기계적 특성 4
• 2.2 적층제조 공정 5
• 2.2.1 FCP 거동에 영향을 미칠 수 있는 적층제조공정 변수 6
• III. 실험 방법 8
• 3.1 시편 8
• 3.1.1 적층제조 조건 8
• 3.1.2 비교용 재료 8
• 3.2 피로균열전파 특성 평가시스템 9
• 3.3 시험조건 9
• 3.3.1 미세조직적 특성 평가 9
• 3.3.2 피로균열전파 시험 9
• IV. 실험결과 및 고찰 11
• 4.1 미세조직 11
• 4.2 인장 특성 및 파괴 인성 11
• 4.3 피로균열전파 특성 12
• V. 결론 25
• 참고 문헌(References) 26