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Investigation on the Microporosity Formation of IN718 Alloy during Laser Cladding Based on Cellular Automaton

Authors
  • Lv, Hao1
  • Li, Zhijie1
  • Li, Xudong1
  • Yang, Kun
  • Li, Fei
  • Xie, Hualong1
  • 1 (X.L.)
Type
Published Article
Journal
Materials
Publisher
MDPI AG
Publication Date
Feb 09, 2021
Volume
14
Issue
4
Identifiers
DOI: 10.3390/ma14040837
PMID: 33572430
PMCID: PMC7916187
Source
PubMed Central
Keywords
License
Green

Abstract

Porosity is one of the most common defects in the laser cladding of Inconel 718 (IN718) alloy, which can reduce the strength and fatigue performance of the components. However, the dynamic formation of microporosity is challenging to observe through experiments directly. In order to explore the formation mechanism of porosities and dynamically reproduce the competitive growth between porosities and dendrite, a multi-scale numerical model was adopted, combined with a cellular automaton (CA) and finite element method (FEM). The decentered square algorithm was adopted to eliminate crystallographic anisotropy and simulate dendrite growth in different orientations. Afterward, based on the formation mechanism of microporosity during solidification, equiaxed and columnar dendrites with porosities were simulated, respectively. Dendrite morphology, porosity morphology, and distribution of solute concentration were obtained during the solidification process. The simulation results were reasonably compared with experimental data. The simulation results of the equiaxed crystal region are close to the experimental data, but the columnar crystal region has a relative error. Finally, the interaction effects of porosities and dendrites under different environmental conditions were discussed. The results suggested that with the increase in the cooling rate, the quantity of porosity nucleation increased and the porosity decreased.

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