Come to think of it, he could just destroy non-vibranium ultron before he became vibranium.

*cough* he was an internet virus, not a physical threat *cough*
It wasn't until Vision cut Ultron from the web is when The Avengers needed to destroy every last bot

Thor did but it was too late. Ultron had already transferred himself.

[image deleted]

what did you do?

Oh, I posted the same image above but accidentally deleted it, so I posted it again