First-Principles Calculation and Mechanical Properties of NaCl–Na2SO4 Composite Water-Soluble Salt Core

International Journal of Metalcasting (2022)Cite this article

Abstract

In this paper, the interfacial energy of various inorganic salts was calculated using the first principle. Finally, NaCl and Na2SO4 were determined as the core materials. A high-strength composite salt core was prepared by optimizing the distribution ratio of the salt core components. The microstructure of the salt core fracture was observed and characterized by SEM and EDS, and the strengthening mechanism of the salt core after the composite was analyzed. The results demonstrated that the strength of the composite salt core was significantly improved compared with the single salt. The bending strength of the salt core reached 24 MPa when the pouring temperature was 800 °C and the molar ratio of NaCl to Na2SO4 was 7:3. Cracks were first generated in the dendrite zone and extended to the surface of the salt core when the salt core was subjected to an external force. After compounding, the structure of the salt core strengthening zone was more complex, the crystal grains were significantly refined, and herringbone patterns appeared. The composite salt blocks are distributed in the strengthening zone and play a leading role in improving the strength of the salt core.

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Keywords

  • first-principles calculation
  • interface energy
  • bending strength
  • strengthening mechanism
DOI