A MULTISCALE FINITE ELEMENT STUDY OF THE RELATION BETWEEN PARTICLE VOLUME FRACTION AND EFFECTIVE MECHANICAL PROPERTIES OF Al-TiB2 COMPOSITES FABRICATED BY SPS

Elad Priel 1,3 Brigit Mittelman 1,2 Nir Trabelsi 1 Or Rahamim 4 Nissim Navi 1,2 Hayun Shmuel 4 Frage Nachum 4
1Mechanical Engineering, Shamoon College of Engineering, Beer-Sheva, Israel
2Materials Engineering, Nuclear Research Center Negev, Beer-Sheva, Israel
3., Rotem Industries Ltd., Mishor Yemin, Israel
4Materials Engineering Department, Ben-Gurion University of the Negev, Beer-Sheva, Israel

Aluminum matrix composites (AMCs) are highly attractive structural materials for the aerospace and automobile industries due to their high strength to weight ratio. Theoretically, mechanical properties of such composites can be tailor made to suit the structural requirements of a specific engineering application, by controling the ceramic particle volume fraction, size and distribution. Powder metallurgy approach allows controlling these parameters.

In the present study, AMC spceimens were fabricated by SPS from a mixture of Al and TiB2 powders with 0-15% volume fraction of TiB2 (average Al and TiB2 particle size were 40 and 2 µm, respectively). Uniaxial compression experiments were conducted in order to study the influence of TiB2 volume fraction on the mechanical response.

A multiscale finite element framework was used to investigate the relation between the microstructure and mechanical properties of the SPS-processed Al-TiB2 composites. First, macro-scale models were used in conjunction with the compression experiments to determine the effective stress strain curves as a function of TiB2 particle volume fraction. Next, micro-scale models of representative volume elements (RVEs) were constructed from SEM images of the un-deformed specimens.

Using the micro-scale models and computational homogenisation methods (CHM) the following topics were examined:

  • The adequate size of the RVE required in order to represent homogeneous mechanical properties.
  • Effect of particle-matrix interface interactions on the resulting effective mechanical properties.
  • Effect of particle distribution on the degree of isotropy of the resulting effective mechanical properites.

Finally, the effective mechanical properties derived from RVE computations were compared to the effective properties derived from the macro-scale models. This comparison provides insight on the role particle-matrix interactions play in the resulting effective mechanical properties.









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