Through a systematic approach this research proposal aims at a comparative study of the mechanical properties of an aluminum-silicon matrix composite reinforced with NbB2 nanoparticles obtained through casting methods: gravity and centrifugal casting. While the first one is more inexpensive, the casting quality obtained with the latter one is higher.  The question to be addressed is: How can the gravity casting method and the matrix composition be modified to close the quality gap between both fabrication techniques?

The primary goal of this research is to formulate an aluminum matrix composition that can attain high strength by gravity and centrifugal casting assisted by the presence of niobium diboride nanoparticles. The matrix will contain silicon levels below the Al-Si eutectic composition to enhance the melt fluidity upon casting. Small levels of cerium will be present to favor the composite ductility, as demonstrated by recent collaborative research between the UPRM and Oak Ridge National Laboratory. The next goal is to study the microstructure of both types of materials (gravity and centrifugally cast) by optical microscopy and ancillary techniques, i.e. x-ray diffraction and thermal analysis. Finally, the mechanical properties of both AMCs will be evaluated via hardness testing, nanoindentation, and three-point bending. The composition will be optimized using subsequent design of experiments to enhance the mechanical strength of the centrifugally cast AMC using as a comparative baseline the strength of the centrifugally cast specimens. The materials will also be tested under TIG welding processing. The final goal of this proposal is to produce a manuscript for a peer-reviewed publication, specialized on composite materials.