Dynamics of pore formation during laser powder bed fusion additive manufacturing

Laser powder bed fusion additive manufacturing is an emerging 3D printing technique for the fabrication of advanced metal components. Widespread adoption of it and similar additive technologies is hampered by poor understanding of laser-metal interactions under such extreme thermal regimes. Here, we elucidate the mechanism of pore formation and liquid-solid interface dynamics during typical laser powder bed fusion conditions using in situ X-ray imaging and multi-physics simulations. Pores are revealed to form during changes in laser scan velocity due to the rapid formation then collapse of deep keyhole depressions in the surface which traps inert shielding gas in the solidifying metal. We develop a universal…

• UD
  U.S. Department of Energy

  Awards: 76SF00515, 32035, DE-AC02, Contract DE-AC52-07NA27344, Contract No. DE-AC02-76SF00515, AC02-76SF00515, 32037, No. DE-AC02-76SF00515, 32038, AC52-07NA27344, DE-AC02-
• OO
  Office of Science

  Awards: AC02-76SF00515, DE-AC02-76SF00515, 32037, 32038, DE-AC02, DE-AC52-07NA27344, 32035, 76SF00515
• OO
  Office of Energy Efficiency and Renewable Energy

  Awards: DE-AC02-76SF00515, 32035, DE-AC52-07NA27344, 32037, 32038
• NN
  National Nuclear Security Administration

  Awards: Contract DE-AC52-07NA27344, DE-AC02-76SF00515, 32035, 32038, DE-AC52-07NA27344, 32037
• AM
  Advanced Manufacturing Office

  Awards: DE-AC52-07NA27344, DE-AC02-76SF00515
• BE
  Basic Energy Sciences

  Awards: DE-AC02, DE-AC02-76SF00515, 76SF00515, Contract No. DE-AC02-76SF00515, AC02-76SF00515, DE-AC52-07NA27344
• OO
  Office of Energy Efficiency
• LL
  Lawrence Livermore National Laboratory

  Awards: Contract DE-AC52-07NA27344, DE-AC52-07NA27344, AC52-07NA27344
• SN
  SLAC National Accelerator Laboratory

  Awards: Contract No. DE-AC02-76SF00515, AC02-76SF00515, DE-AC02-76SF00515