Bismuth and magnesium, somewhat like gold and aluminum, are considered dissimilar metals, so heating or melting these materials and expecting a good metallurgical bond isn't the best way to do things. That's where cold spray technology comes in: if you shoot metal powder at a surface fast enough, it can mechanically and chemically bond to the substrate without ever becoming a liquid.

Image credit to VRC Metal systems

But cold spray systems cost hundreds of thousands if not millions of dollars to own and operate - so is there something we can do instead? It turns out there is! If you concentrate large amounts of force over a small surface area, you can simulate cold spray or explosion welding

(more images and details coming shortly)