Inconel-Steel Multilayers by Liquid Dispersed Metal Powder Bed Fusion: Microstructure, Residual Stress and Property Gradients

Publikationen: Beitrag in FachzeitschriftArtikelForschung(peer-reviewed)

Autoren

  • L.T.G. van de Vorst
  • Jakub Zalesak
  • Juraj Todt
  • Bernhard Sartory
  • Norbert Schell
  • J.W. Hooijmans
  • J.J. Saurwalt

Externe Organisationseinheiten

  • TNO - Netherlands Organisation for Applied Scientific Research
  • Admatec Europe BV
  • Erich-Schmid-Institut für Materialwissenschaft der Österreichischen Akademie der Wissenschaften
  • Materials Center Leoben Forschungs GmbH
  • Helmholtz-Zentrum Hereon, Geesthacht

Abstract

Synthesis of multi-metal hybrid structures with narrow heat affected zones, limited residual stresses and secondary phase occurrence represents a serious scientific and technological challenge. In this work, liquid dispersed metal powder bed fusion was used to additively manufacture a multilayered structure based on alternating Inconel 625 alloy (IN625) and 316 L stainless steel (316 L) layers on a 316 L base plate. Analytical scanning and transmission electron microscopies, high-energy synchrotron X-ray diffraction and nanoindentation analysis reveal sharp compositional, structural and microstructural boundaries between alternating 60 µm thick alloys’ sub-regions and unique microstructures at macro-, micro- and nano-scales. The periodic occurrence of IN625 and 316 L sub-regions is correlated with a cross-sectional hardness increase and decrease and compressive stress decrease and increase, respectively. The laser scanning strategy induced a growth of elongated grains separated by zig-zag low-angle grain boundaries, which correlate with the occurrence of zig-zag cracks propagating in the growth direction. A sharp <110> fiber texture within the 316 L regions turns gradually into a <100> fiber texture in the IN625 regions. The occurrence of the C-like stress gradient with a pronounced surface tensile stress of about 500 MPa is interpreted by the temperature gradient mechanism model. Chemical analysis indicates a formation of reinforcing spherical chromium-metal-oxide nano-dispersoids and demonstrates a possibility for reactive additive manufacturing and microstructural design at the nanoscale, as a remarkable attribute of the deposition process. Finally, the study shows that the novel approach represents an effective tool to combine dissimilar metallic alloys into unique bionic hierarchical microstructures with possible synergetic properties.

Details

OriginalspracheEnglisch
Aufsatznummer101027
FachzeitschriftAdditive Manufacturing
Jahrgang32.2020
AusgabenummerMarch
Frühes Online-Datum31 Dez. 2019
DOIs
StatusVeröffentlicht - März 2020