A research team from the University of Toronto’s Faculty of Applied Science & Engineering has developed a new class of metal matrix composites that combine exceptional strength, lightness, and heat resistance. Created using advanced 3D metal printing, the material is designed to withstand temperatures up to 500 degrees Celsius, making it highly suitable for aerospace and other high-performance applications.
The team, led by Professor Yu Zou of the Department of Materials Science and Engineering (MSE), drew inspiration from the structural principles of reinforced concrete. Their material replicates the concrete-rebar relationship at a microscopic level, where nanoscale metallic precipitates act as reinforcing elements within a matrix of lighter metals.
Unlike traditional aluminum alloys, which lose strength when exposed to high temperatures, the newly engineered composite maintains both stability and resilience. It utilizes a titanium alloy mesh, serving as the “rebar,” combined with a surrounding matrix of aluminum, silicon, and magnesium. Using additive manufacturing, the researchers can precisely control the mesh’s size and geometry, with struts as thin as 0.2 millimeters in diameter.
Additional reinforcement comes from micro-casting and the inclusion of micrometer-sized alumina and silicon nanoprecipitates, which act similarly to aggregate in concrete, improving toughness and durability. Tests have shown that the composite achieves yield strengths of around 700 megapascals at room temperature—several times greater than typical aluminum matrices—and retains 300 to 400 megapascals at 500°C, compared to just 5 megapascals for standard aluminum.
Computer simulations conducted by the team revealed that the material’s resilience at high temperatures results from a unique deformation mechanism called “enhanced twinning,” which helps preserve its structure under heat stress. The discovery, published in Nature Communications, represents a significant advancement in the field of additive manufacturing and advanced materials design.
While scaling the material for industrial use remains costly, the researchers believe that as additive manufacturing becomes more widespread, production efficiency will improve. The new composite could enable lighter, stronger, and more efficient vehicles in aerospace and beyond.
KEY QUOTES:
“Until now, aluminum components have suffered from performance degradation at high temperatures.”
“Basically, the hotter they get, the softer they get, rendering them unsuitable for many applications.”
“In our material, the ‘rebar’ is a mesh made of titanium alloy struts. Because we use a form of additive manufacturing in which we fire lasers at metal powders to heat them into solid metal, we can make this mesh any size we want. The struts can be as small as 0.2 millimetres in diameter.”
“At room temperature, the highest yield strength we got was around 700 megapascals; a typical aluminum matrix would be more like 100 to 150 megapascals.”
“But where it really shines is at high temperature. At 500 Celsius, it has a yield strength of 300 to 400 megapascals, compared to about 5 megapascals for a traditional aluminum matrix. In fact, this new metal composite performs about as well as medium-range steels, but at only about one-third the weight.”
Chenwei Shao, Research Fellow, Zou Laboratory, University of Toronto
“What we found was that at high temperatures, this composite material deforms via a different mechanism than most metals. We called this new mechanism enhanced twinning, and it enables the material to maintain much of its strength, even when it gets very hot.”
Huicong Chen, Postdoctoral Fellow, University of Toronto
“Steel rebar is widely used in the construction industry to improve the structural strength of concrete in buildings and other large structures.”
“New techniques such as additive manufacturing, also known as 3D metal printing, have now enabled us to mimic this structure in the form of a metal matrix composite. This approach gives us new materials with properties we’ve never seen before.”
“We wouldn’t have been able to make this material any other way. It’s true that it still costs a lot to create materials like this at scale, but there are some applications where the high performance will be worth it. And as more companies invest in advanced manufacturing technologies, we will eventually see the cost come down. We think this is an exciting step forward toward stronger, lighter and more efficient vehicles.”
Professor Yu Zou, Department of Materials Science and Engineering, University of Toronto
