Denudation of metal powder layers in laser powder bed fusion processes

Understanding laser interaction with metal powder beds is critical in predicting optimum processing regimes in laser powder bed fusion additive manufacturing of metals. In this work, we study the denudation of metal powders that is observed near the laser scan path as a function of laser parameters and ambient gas pressure. We show that the observed depletion of metal powder particles in the zone immediately surrounding the solidified track is due to a competition between outward metal vapor flux directed away from the laser spot and entrainment of powder particles in a shear flow of gas driven by a metal vapor jet at the melt track. Between atmospheric pressure and ∼10 Torr of Ar gas, the denuded zone width…

• UD
  U.S. Department of Energy
• LD
  Laboratory Directed Research and Development

  Award: 15-ERD-037
• LL
  Lawrence Livermore National Laboratory

  Award: DE-AC52-07NA27344