Niobium, tantalum, titanium and hafnium. Here is the composition of this new alloyalloy whose mechanical properties have amazed scientists. This metal indeed has a very strong resistanceresistance to fracturing, even for a very wide range of temperatures. The alloy indeed exhibits astonishing stability for extreme temperatures ranging from -196°C to 1,200°C! Properties never seen before, which researchers even thought were at the limit of possibility.
Very high resistance to fracture propagation, even at -196°C
This alloy is part of a new class of metalsmetals, called high or medium entropy refractory alloys (RHEA/RMEA). The specificity of these alloys is that they are made up of at least five metals in relatively similar proportions, unlike more traditional alloys which usually consist of a main metal with the addition of small quantities of other elements. This composition gives RHEA/RMEA a particular microstructure which ensures strong stability of the solidsolidand gives them very interesting mechanical properties.
Usually, although these alloys have significant hardness, they are nevertheless very brittle, that is to say very poorly resistant to compressive stress. This is where the new RMEA alloy created a surprise. It turns out to be 25 times more resistant to fracturing than other RMEAs, and this for ambient temperatures of around 25°C, but also for much more extreme temperatures. Usually, materials become more and more brittle as the temperature decreases, but this is not the case for the Nb alloy45Your25Ti15Hf15. Its crystalline structure allows it to prevent the propagation of fractures, even at -196°C! These results were published in the journal Science.
Prospective applications in the fields of aeronautics and space
Many tests are still necessary to identify all the properties of this alloy, but it will undoubtedly find very numerous appsappsparticularly in the fields of aeronautics or space, which require high-strength materials over wide temperature ranges.
