Formation of a porous titanium part under directed energy deposition: Theory and experiment

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2 Citations (Scopus)

Abstract

Despite the enormous number of works devoted to the creation of materials and products by the technologies of selective laser melting (SLM) and electron-beam melting (EBM), there remained a lot of problems connected with the uniqueness of concrete results that cannot be transferred to other three-dimensional production conditions and even to other geometries and dimensions. The current work proposes a model of the process of growth of an object on the basis of minimal experimental information with due consideration of melting and shrinkage. The shrinkage occurs due to the porosity evolution, which affects the volumetric heat capacity and heat conductivity of a melted layer, while in the case of laser radiation, it also affects the coefficient of laser radiation reflection. Titanium was chosen as the object of study, since it is widely used in various additive manufacturing technologies. The work demonstrates that EBM is an appreciably nonstationary process, and its results cannot be assessed by the analysis of temperature in a single track. In the case of laser radiation, the quasi-stationary melting regime at limited time intervals can be established, which is caused by competing factors of heating and heat loss through different mechanisms. The work numerically demonstrates the possibility of obtaining a regular structure, if adequate technological parameters are chosen. This agrees qualitatively with the experiment. To estimate the effective mechanical properties of obtained materials based on the data of their structure, a micromechanical model was used.

Original languageEnglish
Pages (from-to)1-24
Number of pages24
JournalHigh Temperature Material Processes
Volume23
Issue number1
DOIs
Publication statusPublished - 2019

Keywords

  • Convective heat loss
  • Effective properties
  • Nonstationary temperature field
  • Porosity evolution
  • Shrinkage

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Energy Engineering and Power Technology
  • Engineering(all)
  • Spectroscopy
  • Physical and Theoretical Chemistry

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