Japanese scientists have identified a metal that can withstand constant pressure at ultra-high temperatures. This opens up opportunities for new developments in the field of jet engines and gas turbines for power generation.
The first study of its kind, published in Scientific Reports, describes an alloy based on titanium carbide (TiC) and doped molybdenum-silicon-boron (Mo-Si-B), or MoSiBTiC, whose high-temperature strength was determined by constant exposure at temperatures from 1400 ° C to 1600 ° C.
“Our experiments show that MoSiBTiC is incredibly strong when compared to the advanced single-chip nickel superalloys often used in hot compartments in heat engines such as jet engines and gas turbines for power generation,” said lead author Professor Kyosuke Yoshimi of the Tohoku University Graduate School of Engineering. … "This work suggests that MoSiBTiC, as a high-temperature material outside of the nickel-based superalloy range, is a promising candidate for this application."
Yoshimi and his colleagues reported several properties indicating that the alloy can withstand destructive forces at ultra-high temperatures without deformation. They also observed the behavior of the alloy when subjected to increasing forces, when cracks began to form and grow in it, until it eventually broke.
Three-dimensional structure of the first generation of MoSiBTiC alloy.
The efficiency of heat engines is the key to the future extraction of energy from fossil fuels and its further conversion into electricity and propulsion. Improving their functionality can determine how efficiently we convert energy. Creep - The ability of a material to withstand exposure to ultra-high temperatures is an important factor since elevated temperatures and pressures cause deformation. Understanding material creep can help engineers design efficient heat engines that can withstand extreme temperature conditions.
The researchers tested the alloy creep for 400 hours at pressures from 100 to 300 MPa. All experiments were performed on a computer-controlled test setup under vacuum to prevent material oxidation and moisture ingress, which could cause rust to form on the alloy.
The study says the alloy experiences more elongation as the impact is reduced. Scientists explain that this behavior was previously observed only in superplastic materials that can withstand premature failure.
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These detections are an important sign for MoSiBTiC's use in systems operating at extremely high temperatures, such as energy conversion systems in automobiles, propulsion systems and propulsion systems in aviation and rocket science. The researchers report that they have yet to perform several additional microstructural analyzes to fully understand the mechanics of the alloy and its ability to recover from high pressures at high temperatures.
“Our ultimate goal is to invent an innovative ultra-high temperature material that outperforms nickel-based superalloys and replace high-pressure turbine blades made from nickel superalloys with new ultra-high-temperature turbine blades,” says Yoshimi. “Therefore, we must further improve the oxidation resistance of MoSiBTiC by developing an alloy without damaging its exceptional mechanical properties. And this is a difficult task."
Vladimir Guillen