Molybdenum Silicides lead to stronger turbine blades

Turbine blades made out of materials with higher melting temperatures would require less fuel consumption and lead to lower CO2 emissions.

Materials scientists at Japan's Kyoto University investigated the properties of various compositions of molybdenum silicides, with and without additional ternary elements.

Previous research showed that fabricating molybdenum silicide-based composites by pressing and heating their powders - known as powder metallurgy - improved their resistance to fracturing at ambient temperatures but lowered their high-temperature strength, due to the development of silicon dioxide layers within the material.

The Kyoto University team fabricated their molybdenum silicide-based materials using a method known as ‘directional solidification,’ in which molten metal progressively solidifies in a certain direction.

It found that a homogeneous material could be formed by controlling the solidification rate of the molybdenum silicide-based composite during fabrication and by adjusting the amount of the ternary element added to the composite.

The resulting material starts deforming plastically under uniaxial compression above 1,000°C. Also, the material's high-temperature strength increases through microstructure refinement. Adding tantalum to the composite is more effective than adding vanadium, niobium or tungsten for improving the strength of the material at temperatures around 1,400°C.