The Vibranium Arrow was created for use against heavily armored targets. The nature of the arrowhead means it can pass easily through most any form of metal up to and including adamantium. This makes it especially effective against robots such as Ultron and Alkhema.
This trick utilizes Antarctic vibranium, a form of the legendary metal found only within the Savage Lands in Antarctica. Better known as Anti-Metal, this variation produces vibrations that break down the molecular bonds in other metals, causing them to melt. A single piece of Antarctic vibranium can reduce any metal into a liquid or near liquid-like state.