Metallurgical and Materials Transactions A

, Volume 45, Issue 13, pp 6260–6270

An Experimental Investigation into Additive Manufacturing-Induced Residual Stresses in 316L Stainless Steel

Authors

    • Materials Engineering DivisionLawrence Livermore National Laboratory
  • Donald W. Brown
    • Materials Science & Technology DivisionLos Alamos National Laboratory
  • Mukul Kumar
    • Materials Engineering DivisionLawrence Livermore National Laboratory
  • Gilbert F. Gallegos
    • Materials Engineering DivisionLawrence Livermore National Laboratory
  • Wayne E. King
    • Condensed Matter and Materials Division, Physical and Life Sciences DirectorateLawrence Livermore National Laboratory
Article

DOI: 10.1007/s11661-014-2549-x

Cite this article as:
Wu, A.S., Brown, D.W., Kumar, M. et al. Metall and Mat Trans A (2014) 45: 6260. doi:10.1007/s11661-014-2549-x

Abstract

Additive manufacturing (AM) technology provides unique opportunities for producing net-shape geometries at the macroscale through microscale processing. This level of control presents inherent trade-offs necessitating the establishment of quality controls aimed at minimizing undesirable properties, such as porosity and residual stresses. Here, we perform a parametric study into the effects of laser scanning pattern, power, speed, and build direction in powder bed fusion AM on residual stress. In an effort to better understand the factors influencing macroscale residual stresses, a destructive surface residual stress measurement technique (digital image correlation in conjunction with build plate removal and sectioning) has been coupled with a nondestructive volumetric evaluation method (i.e., neutron diffraction). Good agreement between the two measurement techniques is observed. Furthermore, a reduction in residual stress is obtained by decreasing scan island size, increasing island to wall rotation to 45 deg, and increasing applied energy per unit length (laser power/speed). Neutron diffraction measurements reveal that, while in-plane residual stresses are affected by scan island rotation, axial residual stresses are unchanged. We attribute this in-plane behavior to misalignment between the greatest thermal stresses (scan direction) and largest part dimension.

Copyright information

© The Minerals, Metals & Materials Society and ASM International (outside the USA) 2014