Finite Element Method Based Modeling of Alloy 718 Melt Pools Processed by Powder Bed Fusion = 유한요소해석을 이용한 Powder Bed Fusion 용융풀 모델링에 관한 연구

다국어 초록 (Multilingual Abstract)

The melt pool geometries for Alloy 718 powder by process conditions of powder bed fusion (PBF) were predicted using thermal finite element method (FEM). The experiment data for the melt pool width and depth was first measured from single track of Alloy 718 processed by PBF. These results were used to calibrate the penetration depth and absorptivity of laser heat source model as a function of PBF process conditions. Melt pool width and depth were predicted based on calibrated penetration depth and absorptivity, and results of melt pool size were compared with experimental results. Physical suitability and tendency of calibrated values by energy densities were evaluated also.

목차 (Table of Contents)

• List of Tables iii
• List of Figures iv
• Abstract 1
• 1. Introduction 2
• 2. Theory and Background 5
• 2.1 Metal Additive Manufacturing 5
• 2.2.1 Powder Bed Fusion (PBF) Process 5
• 2.2.2 Direct Energy Deposition (DED) Process 9
• 2.2.3 Wire and Arc Additive Manufacturing (WAAM) Process 12
• 2.2 Melt Pool Dynamics 15
• 2.2.1 Melt Pool 15
• 2.2.2 Keyhole and Multiple Reflection 17
• 2.3 Finite Element Method for Powder Bed Fusion 22
• 2.3.1 Heat Transfer Governing Equations 22
• 2.3.2 Thermal Properties 23
• 2.3.3 Heat Source Model 27
• 3. Experimental and Numerical Approach 29
• 3.1 Experimental Approach 29
• 3.2 Numerical Approach 31
• 4. Result and Discussion 39
• 4.1 Experimental Result 39
• 4.2 Numerical Result 41
• 4.2.1 Result of Parametric Studies 41
• 4.2.2 Prediction Results of Melt Pool using Calibrated Penetration Depth and Absorptivity 47
• 4.3 Correlation between Melt Pool Size and Calibrated Penetration Depth and Absorptivity 54
• 5. Conclusion 61
• 6. Appendix 63
• 6.1 Thermal Analysis using ABAQUS 63
• 6.2 Step and Load Input File 64
• 6.3 DFLUX Subroutine Code 65
• Reference 67
• 요약 70