
Ali Tamaddon Page | v
3.2.2 Material: ................................................................................................................................ 36
3.2.3 Fabrication of Laser Powder Bed Fusion (LPBF) parts .................................................. 38
3.2.4 Laser Beam Welding...................................................................................................... 41
3.2.5 Cross section and metallographic preparation ............................................................. 44
3.2.6 Microscopy (area, shape) .............................................................................................. 47
3.2.7 Weld porosity studies ................................................................................................... 47
3.2.8 EDS (chemical composition) .......................................................................................... 49
3.2.9 Microscopy (EBSD) ........................................................................................................ 50
3.2.10 Micro hardness ............................................................................................................. 52
3.3 Second Phase: Main Samples................................................................................................ 53
3.3.1 Design of experiments .......................................................................................................... 53
3.3.2 Fabrication of parts ............................................................................................................... 55
3.3.3 Pre-testing measurement and testing: ................................................................................. 59
3.3.4 Tensile test set up: ................................................................................................................ 59
3.3.5 Fatigue test set up: ............................................................................................................... 62
3.3.6 Post-test examinations: ........................................................................................................ 64
3.4 References ............................................................................................................................ 65
4. Results and Discussion .................................................................................................................. 66
4.1 Introduction .......................................................................................................................... 66
4.2 Pilot samples ......................................................................................................................... 66
4.2.1 Macroscopy ........................................................................................................................... 66
4.2.1.1 Weld appearance and comparison to AWI standards ...................................................... 66
4.2.2 Optical Microscopy ............................................................................................................... 68
4.2.2.1 Weld area measurement, shape, and penetration profile ............................................... 68
4.2.3 Scanning Electron Microscopy .............................................................................................. 73
4.2.3.1 EDS and chemical composition results ............................................................................. 73
4.2.3.2 Microstructure and EBSD results ...................................................................................... 75
4.2.4 Porosity analysis .................................................................................................................... 79
4.2.5 Hardness profile .................................................................................................................... 85
4.3 Main samples ........................................................................................................................ 89
4.3.1 Design of experiments .......................................................................................................... 89
4.3.2 Tensile tests .......................................................................................................................... 90
4.3.2.1 Tensile test setup .......................................................................................................... 90
4.3.2.2 Single piece wrought and LPBF tensile tests ................................................................. 90
4.3.2.3 Porosity analysis – Single piece wrought and LPBF ...................................................... 91
4.3.2.4 Welded wrought to LPBF assembly tensile tests ........................................................ 100