Learned about HEAs (can't remember where), saw some fantastic material properties (rather high yield strengths, solid elastic modulus), and was pleasantly surprised at how much electrolytic corrosion they could resist.

Then one of our money people got a quote from the vendor to see how much it would cost to put it in our product, laughed, and said, "Back to the drawing board you go!" I think it was something like 20x more expensive than a copper alloy contact.