Apple started using technology Liquidmetal in its products still on the iPhone 3G, more specifically in its tool to eject chips. And the partnership continues to work very well.
In 2012 Apple even invested US $ 20 million in Liquidmetal Technologies, and now once again the exclusive agreement between the companies has been renewed (until 2016).
The metal alloy, very light and resistant, has been the subject of many rumors surrounding the Apple world. The technology's own inventor, Atakan Peker, believes that Apple has plans to use it “in a revolutionary product”. I do not doubt that part of the technology was used in the development of the custom metal alloys of the three Apple Watch lines.