A hybrid finite-element and cellular-automaton framework for modeling 3D microstructure of Ti-6Al-4V alloy during solid-solid phase transformation in additive manufacturing

Shaohua Chen, Yaopengxiao Xu, Yang Jiao

Research output: Contribution to journalArticle

5 Scopus citations

Abstract

Additive manufacturing such as selective laser sintering and electron beam melting has become a popular technique which enables one to build near-net-shape product from packed powders. The performance and properties of the manufactured product strongly depends on its material microstructure, which is in turn determined by the processing conditions including beam power density, spot size, scanning speed and path etc. In this paper, we develop a computational framework that integrates the finite element method (FEM) and cellular automaton (CA) simulation to model the 3D microstructure of additively manufactured Ti-6Al-4V alloy, focusing on the β → α + β transition pathway in a consolidated alloy region as the power source moves away from this region. Specifically, the transient temperature field resulted from a scanning laser/electron beam following a zig-zag path is first obtained by solving nonlinear heat transfer equations using the FEM. Next, a CA model for the β → α + β phase transformation in the consolidated alloy is developed which explicitly takes into account the temperature dependent heterogeneous nucleation and anisotropic growth of α grains from the parent β phase field. We verify our model by reproducing the overall transition kinetics predicted by the Johnson-Mehl-Avrami-Kolmogorov theory under a typical processing condition and by quantitatively comparing our simulation results with available experimental data. The utility of the model is further demonstrated by generating large-field realistic 3D alloy microstructures for subsequent structure-sensitive micro-mechanical analysis. In addition, we employ our model to generate a wide spectrum of alloy microstructures corresponding to different processing conditions for establishing quantitative process-structure relations for the system.

Original languageEnglish (US)
Article number045011
JournalModelling and Simulation in Materials Science and Engineering
Volume26
Issue number4
DOIs
StatePublished - Apr 30 2018

Keywords

  • additive manufacturing
  • cellular automaton model
  • finite element model
  • microstructure evolution
  • phase transformation
  • Ti-6Al-4V

ASJC Scopus subject areas

  • Modeling and Simulation
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Computer Science Applications

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