An alloy is a mixture composed primarily of two or more elements, which may or may not be metals. The addition of one or more secondary elements is specifically designed to modify the mechanical, thermal, or chemical properties of the primary components, often resulting in a material superior to the pure constituent elements. These composite materials are fundamental in engineering and industry, used extensively in structural components, electronics, and advanced scientific equipment. The physical properties of an alloy, such as hardness, corrosion resistance, or conductivity, are determined by the crystalline structure and the ratios of the constituent atoms, rather than simply being a weighted average of the pure metals involved.