Journal of Materials Research and Technology (May 2024)

Microstructure and failure mechanism of Y2O3 coating on the W fiber in Wf/W composites during field assisted sintering

  • C. Chen,
  • Y. Chen,
  • X. Han,
  • K.L. Li,
  • S. Wang,
  • Y.F. Zhang,
  • Y.R. Mao,
  • J.W. Coenen,
  • J. Wang,
  • L.M. Luo

Journal volume & issue
Vol. 30
pp. 8661 – 8670

Abstract

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For tungsten fiber-reinforced tungsten matrix (Wf/W) composites, the interfacial microstructure is essential for the improvement of mechanical properties. The Y2O3 coating deposited on the W fiber has been applied to modify the interface between the W matrix and W fiber. However, the Y2O3 coating on the W fiber is usually fractured and dispersed into the W matrix as large particles after sintering. In this study, the microstructure of the Y2O3 coating on the W fiber in Wf/W composites was studied. And the failure mechanism of Y2O3 interface during field assisted sintering was investigated through finite element analysis (FEA). The reasons for the fracture of the Y2O3 interface can be attributed to the transformation of the Y2O3 coating from cubic to face centered cubic (FCC) crystal structure, the large lattice misfit of 49.0% at the interface, the large difference of the elastic modulus and thermal expansion coefficient between W and FCC-Y2O3. In order to avoid the fracture of Y2O3 interface during sintering, the finite element analysis was used to modify the processing parameters of Wf/W composites, including the sintering temperature, pressure, particle size of W powder and thickness of the Y2O3 coating. And the simulation results were consistent with the experimental results.

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