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How to Eliminate Porosity in 3D Printed Titanium Alloys

Several approaches can be used to eliminate porosity in 3D-printed titanium alloys:
Powder Density Control: Increasing the powder packing density can reduce the porosity within the formed parts.

Parameter Adjustment: Adjusting repair processes like increasing laser power and reducing beam movement speed can eliminate fusion defects.

Hot Isostatic Pressing (HIP): Using hot isostatic pressing can eliminate printing pores. However, it may also disrupt the original 3D-printed material structure, potentially affecting fatigue performance.

NAMP (Net-Additive Manufacturing Process): A novel process involving defect and microstructure control in separate steps to produce nearly pore-free titanium alloy. This method uses a specific heat treatment window for the Ti-6Al-4V alloy, which allows for the refinement of the microstructure without causing pore recurrence or the formation of undesirable α phase enrichment at grain boundaries.

Preheating and Controlled Cooling: Preheating before laser melting and maintaining insulation and slow cooling after forming can release residual stress and effectively suppress crack formation.

Understanding Phase Transformation and Grain Growth: Research indicates that understanding the asynchronous nature of phase transformation and grain growth can provide solutions for improving the fatigue resistance of titanium alloys.

The NAMP technique is particularly effective in suppressing the reappearance of micro-pores, effectively reconstructing the alloy's structure6. By using the NAMP process, researchers have successfully produced a nearly pore-free titanium alloy with significantly enhanced fatigue strength.