Laser powder bed fusion (L-PBF) with point-by-point

line-by-line

body-by-body forming often produces defects and that are difficult to control

and porosity is one of the typical defects that affect the quality of L-PBF formed parts. Therefore

the study on the porosity defects is necessary to improve the mechanical properties of L-PBF formed parts. A numerical model for mesoscopic scale of the melt pool in the L-PBF forming of TA15 titanium alloy is established based on the discrete element method (DEM)

and the volume of fluid (VOF) method is used to trace the free surface of the melt pool for simulation

and the computational fluid dynamics (CFD) FLOW-3D software is used to simulate the porosity defects in the L-PBF forming of TA15 titanium alloy. The effect of the laser power P and scanning speed v on the melt pool porosity defects was investigated. The results show that as the laser power increases and the scanning speed decreases

the melt pool depth tends to increase and the number of pores increases

and the laser energy density threshold for pores in the melt pool is E=0.043 3 MJ/(m·s1/2).