Is this what is happening with gold and silver coins that have been lost in shipwrecks and when recovered centuries later have formed a mass of metal that is joined together but doesn’t look “melted” per se? Like this:
Put two same solid materials next to each other and they combine into one without liquid transition?
I’m blanking on the name but there are small spherical stones that have been discrete objects separate from the surrounding rock for in some cases billions of years.
Others have mentioned gauge blocks that are wrung together.
I once read an article (sorry, no cite) that said physicists still do not understand the physical mechanism for why gauge blocks stick together.
The article said it was not due to Van Der Waal Forces. It also said it was not due to air pressure, since experiments have shown gauge blocks can be wrung together in a vacuum.
According to the article, the only explanation to-date is “molecular forces.”
Is Casimir force a factor?