Effect of processing parameters on surface roughness, porosity and cracking of as-built IN738LC parts fabricated by laser powder bed fusion

•Processing parameters have significant effect on printing qualities during LPBF.•Rayleigh instability and Marangoni convection can deteriorate the surface quality.•Pores are caused by lack of fusion and keyhole regarding to different VEDs.•Residual stress and solidification time affect crack densit...

Full description

Saved in:
Bibliographic Details
Published in:Journal of materials processing technology 2020-11, Vol.285, p.116788, Article 116788
Main Authors: Guo, Chuan, Li, Sheng, Shi, Shi, Li, Xinggang, Hu, Xiaogang, Zhu, Qiang, Ward, R. Mark
Format: Article
Language:English
Subjects:
Computed tomography
Crack density
Flux density
Laser powder bed fusion
Lasers
Marangoni convection
Melting
Nickel base alloys
Nickel-Based superalloy
Porosity
Powder beds
Process parameters
Processing parameters
Rapid prototyping
Regression analysis
Residual stress
Solidification
Superalloys
Surface properties
Surface roughness
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:•Processing parameters have significant effect on printing qualities during LPBF.•Rayleigh instability and Marangoni convection can deteriorate the surface quality.•Pores are caused by lack of fusion and keyhole regarding to different VEDs.•Residual stress and solidification time affect crack density related to parameters.•VED of ∼ 48 J/mm3 is optimal for building IN738LC components by LPBF. An investigation was conducted to understand how different parameters, namely laser power, scan speed and hatch spacing, influence the printing qualities, i.e. surface roughness, porosity and crack density of the nickel-based superalloy Inconel 738LC during laser powder bed fusion. Insufficient overlap, Plateau–Rayleigh instability and Marangoni convection were identified and characterized as the factors that could deteriorate the surface quality of as-built IN738LC parts. Two leading causes of pore were determined by metallographic analysis and computed tomography as lack of fusion and keyhole, which were attributed to different energy input densities. Crack density was measured by metallographic observation. Residual stress and the time for solidification of melt were identified as the key factors that affected the crack density. Finally, the relationships between the printing qualities and volume energy density were established by regression analysis, and the VED of ∼ 48 J/mm3 was optimal for fabricating IN738LC in the LPBF process
ISSN:0924-0136
1873-4774
DOI:10.1016/j.jmatprotec.2020.116788