[TXnMA]

Also, there is a wealth of intermetallic compounds (products of actual chemical reactions between metals) to be explored.

Some are detrimental in specific applications -- like the decades-known Au₅AL₂ intermetallic reaction (aka "Purple Plague") that cause failures of bonds between gold wires and aluminum IC metallization...

That doesn't mean that it (or other stoichometric ratio compositions) could not be useful for other purposes...

[TXnMA]

RE our recent discussion of allotropes, etc., here's yet another carbon form with almost-unbelievable properties:

"Diamene" -- 'Wonder material' that is as flexible as tin foil but becomes harder than a diamond when it's hit by a bullet could lead to ultra-light body armour

Two (no more, no less) layers of graphene together can exceed the hardness and strength of diamond when stressed:

As I said, we now understand the elements of the periodic table fairly well. Now, the materials science door is opening into a whole new world of nano and micro-scale elemental structures.

Next? Products of reactions between nanostructures...?

We've come a long way in the last century. There's no telling where a culture with a few millennia of a head start might be in their knowledge and applications of materials...