Jonathan Lee prepares to test the strength of the new alloy MFSC-398, which he co-invented with PoShou Chen, a scientist with Morgan Research Corp. The new high-strength aluminum-silicon alloy promises to lower engine emissions and improve gas mileage in cars, boats, and recreational vehicles.
A new high-strength, aluminum-silicon alloy, developed at NASA's Marshall Space Flight Center, Huntsville, Ala., can be used for high-temperature cast components in engines to help lower emissions. This alloy, called MSFC-398, enables engine-part manufacturers to use less material, thus reducing a part's weight and cost and improving gas mileage, engine performance, and engine durability.
"Increasingly stringent exhaust-emission regulations for internal combustion engines have forced piston designers into a redesign to lower emissions," says alloy co-inventor Jonathan Lee, a NASA structural materials engineer. "The current modification is to reduce the piston's crevice volume — the air gap between the piston wall and the cylinder bore — by moving the top piston ring closer to the top of the piston crown."
Such a modification promises to be a key to reaching the goal of making today's high-performance gasoline and diesel engines meet tougher exhaust standards.
To accomplish this, engine makers needed a strong, low-cost alloy that would allow them to make the piston-crown depth thinner — yet still curb piston failure caused by high work and heat loads. In addition to piston re-design, the new alloy will work well for connecting rods, actuators, brake calipers, and rotors.
MSFC-398 is wear-resistant and exhibits dramatic strength at temperatures as high as 500° to 700° F. When tested at 600° F, it is 3 to 4 stronger than conventional cast aluminum alloys. The new metal can also be produced at a projected cost of less than $1/lb. As an additional cost savings over machining, MSFC-398 pours as a molten metal into conventional steel molds or diecasting molds to create specially shaped parts.
Two U.S. patents have been awarded with other domestic patents pending. An international patent is pending for the technology as well. Through NASA's Technology Transfer program, non-exclusive licenses to develop new products from the improved alloy have been awarded to Advanced Materials Technology Inc., Manitowoc, Wis.; Swan Metal Composites Inc., Wood-inville, Wash.; and Eck Industries, Manitowoc, Wis. NASA is continuing to seek U.S. industries as partners to further transfer this technology to the public and private sectors.