US scientists’ new alloys cut truck engine weight by 15%, boost fuel efficiency by over 10%

Researchers at the Department of Energy’s Oak Ridge National Laboratory (ORNL) have created advanced aluminum alloys that could allow for far lighter truck engines still capable of operating at higher temperatures.
The alloys have successfully met the demanding strength and durability requirements of General Motors’ new low-mass, high-efficiency (LMHE) medium-duty truck engine.
Testing under a cooperative research and development agreement showed more than 10 percent improvement in fuel efficiency and a 15 percent reduction in engine weight compared to conventional designs.
New alloys enable reduced mass and superior high-temperature performance
Commercial truck engines, such as those in GM’s Chevrolet Silverado 3500, must endure heavy loads and extended operation.
Traditional materials capable of withstanding these conditions are dense, which hurts fuel economy. Lighter alternatives often fail under the elevated temperatures and pressures of high-performance engines.
According to an ORNL press statement, their team’s new alloys resolve this conflict by providing both reduced mass and superior high-temperature performance.
The ORNL researchers tested two aluminum alloys. One of these, cast ACMZ (AlCuMnZr), was used for the LMHE engine’s cylinder heads and block. It offers high strength at low cost while resisting intense heat and mechanical stress.
The second, DuAlumin3D, is a 3D-printable alloy developed for pistons. It combines lightweight construction with what ORNL describes as the strongest known combination of strength and durability at extreme temperatures for a structural aluminum.
“The shared goal between ORNL and GM was to demonstrate next-generation engines for high-volume trucks that are lighter, lower-cost, and more efficient, all without sacrificing power and performance,” said Allen Haynes, director of the ORNL-led TTO Powertrain Materials Core Program consortium.
“This is a remarkable set of combined outcomes by the GM design team,” added Amit Shyam, who leads ORNL’s Alloy Behavior and Design Group. “Any weight shaved off an engine equates to more miles per gallon for the average driver, saving not only energy, but money.”
An accelerated alloy design approach
The GM-led project, which included ORNL and multiple suppliers, passed rigorous performance and durability tests. In 2025, it earned an R&D 100 Award and a DOE 2025 Team Award. Both ACMZ and DuAlumin3D had previously received R&D 100 honors for earlier breakthroughs.
According to the ORNL press statement, the collaboration integrated materials science, advanced manufacturing, combustion engineering, and computational modeling. ORNL’s accelerated alloy design approach compresses the timeline from concept to prototype application to two to four years. This is a massive reduction when compared with the traditional 10 to 15 years. The shorter lead time reduces costs and risks in moving laboratory innovations to commercial use.
The project received support from the Department of Energy’s Transportation Technologies Office and Advanced Materials and Manufacturing Technologies Office. The successful demonstration shows how targeted federal research can move quickly from laboratory alloys to proven engine components, giving US truck manufacturers a practical path to lighter, more fuel-efficient vehicles that maintain full performance and durability.