First things first, I came across this interesting article after which I stumbled upon this mysterious composite of an aluminium oxide and silicon carbide. Specifically stating this on wikipedia:
"In 1982 an exceptionally strong composite of aluminium oxide and silicon carbide whiskers was discovered. Development of this laboratory-produced composite to a commercial product took only three years. In 1985, the first commercial cutting tools made from this alumina and silicon carbide whisker-reinforced composite were introduced into the market."
leaving me with this
So, Does you know what this mystery aluminium oxide is? And what other aluminium oxides could be used for this strong composite?