J. Mater. Sci. Technol. ›› 2021, Vol. 69: 96-105.DOI: 10.1016/j.jmst.2020.08.022

• Research Article • Previous Articles     Next Articles

Microstructural banding of directed energy deposition-additively manufactured 316L stainless steel

Yoon Hwaa, Christopher S. Kumaia, Thomas M. Devinea,*(), Nancy Yangb, Joshua K. Yeeb, Ryan Hardwickb, Kai Burgmannb   

  1. a Department of Materials Science and Engineering, University of California, Berkeley, CA, 94720, USA
    b Sandia National Laboratory, Livermore, CA, 94551, USA
  • Received:2020-05-19 Revised:2020-05-27 Accepted:2020-05-30 Published:2021-04-10 Online:2021-05-15
  • Contact: Thomas M. Devine
  • About author:*E-mail address: devine@berkeley.edu (T.M. Devine).

Abstract:

The microstructures of 316 L stainless steel created by rapid solidification are investigated by comparing the similar microstructures of individual hatches of directed energy deposition additive manufacturing (DED-AM) and those of single, laser surface-melted tracks formed on a solid plate. High recoil pressure, which is exponentially dependent on the laser beam power density, induces convection of the melt pool, which causes formation of microstructural bands in the as-solidified microstructure. The microstructural bands are associated with changes in the chromium concentration and are a significant component of the inhomogeneous microstructure of DED-AM.

Key words: Additive manufacturing, Directed energy deposition, Stainless steel, Rapid solidification, Recoil pressure, Microstructure