I take umbrage at all these popsci articles that keep breathlessly insisting that the new wondermaterial is as "strong" as steel without meaningfully specifying how. Because inevitably it only matches just one mechanical property of steel, if it even manages that (so also look out for weasel words like "nearly as strong as steel").
As strong in terms of tensile strength? Shear strength? Hardness? Elastic modulus? Abrasion resistance?
In this case it's compressive strength. No other properties are mentioned except weight. That's not terribly impressive from a mechanical engineering standpoint. From a chemistry standpoint, sure. But steel -- even then, there are oodles of potential steel alloys -- has a rough compressive strength ranging from 500-ish to a maximum of about 1500 MPa. Big whoop. Most ceramics meet or handily exceed that, and quite a lot of them are significantly lighter than steel. So why don't we build airplanes out of those? Because their other properties are completely unsuitable for the task, especially for large pieces. In particular they're much too brittle.
You want to know what else has a compressive (and tensile!) strength of up to 500 MPa? Aluminum. Guess what we build airplanes out of.
