An alloy is a mixture or metallic solid solution composed of two or more elements. Three methods for preparation of alloys: 1.When a molten metal is mixed with another solid metal. there are two mechanisms that can cause an alloy to form, called atom exchange and the interstitial mechanism. 2. When a molten metal such as aluminium, titanium, and copper, are heat-treatable and quenched (cooled quickly), and then harden over time. After quenching a ternary alloy of aluminium, copper, and magnesium.It has name precipitation hardening alloys 3. When two solid metals is mixed and then are melted together.