The "AlAu4" structure comment got me reading about the aluminum-gold phase diagram. One component there, AlAu2, was infamous in the early IC industry for caus

The "AlAu4" structure comment got me reading about the aluminum-gold phase diagram. One component there, AlAu2, was infamous in the early IC industry for causing chip failures ("purple plague"). https://en.wikipedia.org/wiki/Gold%E2%80%93aluminium_intermetallic https://en.wikipedia.org/wiki/Gold%E2%80%93aluminium_interme...