A team of scientists at the University of Toronto has developed a new lightweight titanium alloy composite with potential applications in sectors like aerospace, defense and automotive.

The team built the material using assorted metallic alloys bound by nanoscale precipitates, thus mimicking the structure of reinforced concrete. Meanwhile, 3D-printed titanium alloy struts mirror the steel rebar in reinforced concrete, while a method called ‘micro-casting,’ which was used to construct a matrix of other elements including aluminum, silicon and magnesium, that functions like cement.

Source: University of Toronto Engineering

Further, added strength is ensured by micrometer-sized particles of alumina and silicon nanoprecipitates, which play the role of gravel or aggregate in concrete. 

The team noted that the material in the ‘rebar’ is a mesh composed of titanium alloy struts. Using a form of additive manufacturing wherein lasers are fired at metal powders to heat them into solid metal, the mesh can be made in any size. For instance, the struts can be made as small as 0.2 mm in diameter.

In the lab, tests were performed on the material and the researchers determined that it delivers exceptional strength in relation to its mass, especially at high temperatures where other materials are often compromised. The team determined that this strength, as revealed by computer models, was due to the composite deforming via a different mechanism than most metals.

At room temperature, the highest yield strength achieved was around 700 megapascals while a standard aluminum matrix would achieve about 100 to 150 megapascals.

Yet, at high temperatures — around 500° C — the material achieved a yield strength of 300 to 400 megapascals, versus the roughly 5 megapascals achieved for a traditional aluminum matrix. Overall, the team concluded that the new metal composite performs similarly to medium-range steels — but at just about one-third the weight.

An article detailing the material, “Achieving improved mechanical performance in aluminum matrix composites with rebar-reinforced concrete-inspired structures,” appears in the journal Nature Communications.