The recipes I discovered so far;
Copper + Tin = Bronze
Copper + Gold = Shakudo
Copper + Silver = Sterling Silver
Copper + Nickel = Monel Metal
Copper + Aluminium = Duralumin
Iron + Nickel = Nickel Steel
Iron + Tungsten = Tool Steel
Gold + Silver = Electrum
Lead + Tin = Soldering Iron
Copper + Iron + Gold = Antanium
Edit: I just added even more recipes. If anyone discovers more, please reply here.