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

Research output: Contribution to journalArticlepeer-review

Authors

  • Chuan Guo
  • Shi Shi
  • Xinggang Li
  • Xiaogang Hu
  • Qiang Zhu

Colleges, School and Institutes

External organisations

  • Department of Mechanical and Energy Engineering
  • South University of Science and Technology of China
  • College of Computer Science and Software Engineering, Shenzhen University, Shenzhen, China.

Abstract

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

Details

Original languageEnglish
Article number116788
Number of pages17
JournalJournal of Materials Processing Technology
Volume285
Early online date1 Jun 2020
Publication statusPublished - Nov 2020

Keywords

  • Crack density, Laser powder bed fusion, Nickel-Based superalloy, Porosity, Processing parameters, Surface roughness