New aluminum-antimony alloy is expected to improve energy efficiency of automotive engines and promote application of rare earth products

Rare earth elements play an important role in the electronics industry, new energy sources and other modern technologies. For modern wind power and hybrid cars, for example, permanent magnets rely on rare earth yttrium and strontium.

The proportion of barium in most rare earth ores can reach more than half, including rare earth ore in the United States, so the balance of supply and demand for barium elements is a problem for rare earth producers. In the most common rare earth ore in the United States, the content of antimony is three times that of antimony, which is more than 500 times that of antimony. Aluminum-beryllium alloys are expected to enhance the demand and application value of niobium elements, thereby promoting domestic rare earth mining.

"Modern energy technologies require the use of rare earth elements," said Rios. "But when we separate rare earths, we will have a large number of surplus elements that are limited in use - helium and thorium." If a new type of aluminum alloy is placed in an internal combustion engine, the by-product from the rare earth mining can be rapidly transformed into a more valuable product.

“The aluminum market is huge,” said Rios. “Aluminum is used in the automotive industry in large quantities, so even small components will enter the market and will increase demand.” Even if the new aluminum-bismuth alloy only has a market share of 1%, the demand for bismuth will also reach 3,000 tons. Components made from the new aluminum-bismuth alloy have many advantages over existing products such as low cost, high plasticity, low heat treatment requirements, and exceptionally high temperature stability.

"A lot of alloys with special properties are generally hard to cast," said David Weiss, vice president of R&D at Eck Industries. "But aluminum-bismuth alloys have the same casting characteristics as aluminum-silicon alloys."

The key to the high temperature properties of the alloy is the specific aluminum-niobium mixture or compound formed during melting or casting. The melting temperature of this intermetallic compound is above 2000 Å.

The heat resistance of the aluminum-beryllium alloy is more suitable for the internal combustion engine, and actual measurements show that the new alloy remains stable at 300° C. (572° C.), and the conventional alloy has already begun to melt at this temperature. In addition, the stability of the new alloy reduces the need for heat treatment.

Aluminum-antimony alloys not only directly increase the engine's fuel efficiency through operating temperatures, but also improve fuel efficiency through the use of small aluminum base components or aluminum alloys instead of cast iron, such as cylinder columns, gearboxes, and cylinder heads.

The research team has made prototypes of aircraft cylinder heads into traditional sand molds. The team also made a fully functional cylinder head of a fossil fuel engine into a 3d printed sand mold. This is the first successful engine test in the same category at the Oak Ridge National Laboratory Transportation Research Center. The exhaust temperature of the process display engine exceeds 600°C.

"The 3D printing model is generally difficult to achieve," said Oak Ridge Labs Zachary. "But due to the extraordinary plasticity of aluminum-bismuth alloys, this is completely achievable."

The new aluminum-bismuth alloy was developed by scientists from Oak Ridge National Laboratory and Eck Industries. Eck Industrial's researchers are responsible for technical support for aluminum castings. Lawrence Livermore National Laboratory researchers use simultaneous acceleration source x-ray computed tomography to analyze aluminum-antimony castings.