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Title: Dimensionless numbers in additive manufacturing

In this paper, the effects of many process variables and alloy properties on the structure and properties of additively manufactured parts are examined using four dimensionless numbers. The structure and properties of components made from 316 Stainless steel, Ti-6Al-4V, and Inconel 718 powders for various dimensionless heat inputs, Peclet numbers, Marangoni numbers, and Fourier numbers are studied. Temperature fields, cooling rates, solidification parameters, lack of fusion defects, and thermal strains are examined using a well-tested three-dimensional transient heat transfer and fluid flow model. The results show that lack of fusion defects in the fabricated parts can be minimized by strengthening interlayer bonding using high values of dimensionless heat input. The formation of harmful intermetallics such as laves phases in Inconel 718 can be suppressed using low heat input that results in a small molten pool, a steep temperature gradient, and a fast cooling rate. Improved interlayer bonding can be achieved at high Marangoni numbers, which results in vigorous circulation of liquid metal, larger pool dimensions, and greater depth of penetration. Finally, a high Fourier number ensures rapid cooling, low thermal distortion, and a high ratio of temperature gradient to the solidification growth rate with a greater tendency of plane frontmore » solidification.« less
Authors:
 [1] ;  [1] ; ORCiD logo [1] ;  [1]
  1. Pennsylvania State Univ., University Park, PA (United States). Dept. of Materials Science and Engineering
Publication Date:
Grant/Contract Number:
NE0008280; 179466
Type:
Accepted Manuscript
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 121; Journal Issue: 6; Journal ID: ISSN 0021-8979
Publisher:
American Institute of Physics (AIP)
Research Org:
Pennsylvania State Univ., University Park, PA (United States)
Sponsoring Org:
USDOE Office of Nuclear Energy (NE); American Welding Society (United States)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; solidification; thermal properties; melt deposition; powders; fluid flows; thermomechanical effects; liquid metals; welding; microstructural properties
OSTI Identifier:
1465327
Alternate Identifier(s):
OSTI ID: 1361777