Comic Books

Aight, you ready for some geek talk? If not, boy did you ask the wrong question!

So, fictional materials. That's the only possible starting point because it means that the properties of fictional materials are exactly what the writer/editor wants them to be, no matter what lore says. So, you have to take that into account in comics, or in purely text based fiction. Since what you're asking also includes going away from print media you a new format, the issue of "writeritis" gets amplified by directors, producers, and test screenings.

With that being said, Thanos breaking a vibranium shield with his uru sword is lore friendly.

Vibranium is an energy and vibration absorbing/dispersing material. I've never seen a definitive answer as to exactly what it is, as in an element, an alloy, or something transformed. But it is not from earth in origin.

Uru originates from one place in the standard marvel universe, and is essentially a super dense metal created by the heat and pressures of a star. But but not a regular one, one from asgardian territory, so magic is involved. This suggests that it is something akin to it being one of those elements formed only in absurd conditions that would generate an atomic number way higher than the 118 that our real world has.

This means that uru is denser, harder, and may have properties that would be able to do weird quantum shit, like maybe splitting praise otherwise unbreakable bonds.

Since Thanos is a freak of physical strength to begin with, and has used magic as well, if he's swinging a sword made of a magical super element, he's also likely to be swinging with forces not found outside of cosmic events. And he's casting a spell as he does so (in equivalency).

Since he's using an uru sword against a human made object that has very little established anti-magic properties and has been shown in both comics and the mcu to be damagable by more mundane forces, Thanos straight up wrecking the shield isn't out of bounds.

Think of it like our best bunkers that can survive a nuke being hit by a giant depleted uranium rod flung from high orbit. There's not going to be anything but rubble left, even though a nuke with the fission reaction wouldn't do much damage.

Thanos is just that strong compared to most things, and uru is essentially the most dense material in the various marvel universes. Plus magic.

That sword would be able to cut right through wolverine. Adamantium is, in most versions from the comics, way denser than Vibranium, and has the benefit of being extremely difficult to alter once its shape is ser. But uru can damage adamantium, just like adamantium can damage vibranium in the right circumstances.

None of those materials are impervious to everything, by canon. They're just absurdly difficult to damage.

Based on what I remember of the movies in specific, vibranium isn't as durable as the comics version. But uru is portrayed pretty damn close to comics properties, so for movie uru to damage movie vibranium makes sense