The need for materials capable of surviving and thriving in applications under severe regimes (such as aeronautic, automotive, renewable energies, military and information technologies) where traditional materials often fail is becoming urgent. In particular, materials possessing high stiffness to weight ratio and high temperature creep and wear resistance are needed in order to face the technological challenges of the 21st century.
Metal matrix composites materials (MMCs) may represent the solution to this specific request of properties, especially at high temperature. However, MMCs still find only niche applications because of the high cost process and technological limitations.
In response to this, a team of researchers from University of Padova (Biasetto et al.) have developed titanium matrix composites starting from silicon based polymers and Ti6Al4V powders in the micro size range. A high-energy ball-milling process drove to the formation of a layered structure of polymer and metal. A thermal treatment at high temperature was run with multiple objectives: decompose the polymer, induce the reaction between the polymeric residues (both gaseous and solids) and the titanium matrix and eventually sintering the metallic matrix with reaction products. The final material resulted in a Ti6Al4V matrix where TiC and Ti5Si3 were dispersed at the micrometer range. Hardness and wear resistance were consistently improved compared to standard Ti6Al4V alloy.
The use of a Si-based polymer as precursor for a ceramic reinforcing phase in metal matrix composites may represent the way forward for the production of MMCs mainly due to the versatility of the process and the withstanding properties of the final material.
