Researchers at Cambridge University, England, announce that they have designed a class of iron alloys in which a high density of strong interfaces can be created by heat treatment alone. In this nanostructure-controlled high-strength bainitic steel, the thickness of bainitic ferrite platelets is controlled between 20 and 50 nm. Nanostructured super bainitic steel achieves the extremely high strength of 2.5 GPa by heating at 200°C for ten days. The steel contains silicon, molybdenum, chromium, and manganese. The super bainite can be made into large structures at low cost, and thousands of metric tons have already been manufactured. However, it cannot be welded, limiting its applications.
Developed by a team led by Prof. Harry Bhadashia, “The good points are that we can make this large in all three dimensions with an incredibly simple heat treatment. And the steel itself is quite cheap to make. There’s nothing really expensive about it. So, in any application where we require a combination of strength and toughness, this is perfect.” The drawback is that because it is so strong, it cannot be welded. Therefore, a bridge could not be made of it. Large structures need to be joined at some point, and this material cannot be welded at the moment. The alloy was discussed in a paper published in the Science and Technology of Advanced Materials (“The first bulk nanostructured metal”), by Prof. H.K. Bhadeshia .
Read an interview with Prof. Bhadeshia.
Contact Prof. Bhadeshia at [email protected] .
