Microstructure-Properties Modelling of Tungsten-Copper (W-Cu)
composite
G. V. Franks1,2, P. J. Mignone1,2, M. Wang1,2, D. P. Riley1,2,3, T. Finlayson1, M. P.
Echlin4, T. M. Pollock4
1Chemical and Biomolecular Engineering, University of Melbourne, Parkville, Vic,
3010, Australia;
2 Defence Materials Technology Centre, Hawthorn, Vic, 3122, Australia;
3 Institute of Materials Engineering, Australian Nuclear Science and Technology
Organisation, Lucas Heights, NSW 2234, Australia;
4 University of Californina at Santa Barbara, Materials, CA, 93106, USA;
e: gvfranks@unimelb.edu.au
Tungsten-copper (W-Cu) composites are useful at ultrahigh temperature to
protect cargos during re-entry and hypersonic flight as sacrificial ablative layers. The
copper melts and evaporates during the materials operation. The evaporation keeps
the temperature below the melting temperature of the tungsten. The tungsten matrix
maintains its strength while the interconnected copper phase (typically 10 to 20% of
the material) provides a pathway to the surface for copper transport. The aim of the
project is to be able to predict material properties at extreme conditions not readily
accessible to experimental study. The material microstructure has been captured
with a novel tri-beam serial sectioning apparatus at the University of California at
Santa Barbara [1]. The 2D slices are treated by image processing and stacked to
produce a virtual 3D microstructure as shown in Figure 1. The virtual microstructure
is used to simulate the thermal and mechanical properties of the composite. Thermal
properties are predicted by Lattice Monte Carlo method while mechanical behaviour
is predicted by Finite Element Analysis. Results are compared to experimentally
measured properties.
a)
b)
c)
Figure 1. Steps to construct virtual 3D microstructure (a) capture serial sectioned
SEM images with tri-beam [1], (b) segment images and (c) stack images and mesh.
References
[1]
M. P. Echlin, A. Mottura, M. Wang, P. J. Mignone, D. P. Riley, G. V. Franks
and T. M. Pollock, “Three-dimensional characterization of the permeability of W-Cu
composites using a new “TriBeam” technique”, Acta Materialia, 64, 307-315 (2014)