Metals - Alloys and their Properties

Objective: State that alloys can be harder and stronger than the pure metals and are more useful

What are Alloys?

An alloy is a mixture of two or more metals, or a metal with a non-metal. The metals are mixed to enhance certain properties that are not present in the pure metals.

Why are Alloys More Useful?

Pure metals often have properties that limit their use in certain applications. Alloys are designed to overcome these limitations by combining the desirable properties of different metals.

Properties of Alloys

Alloys often exhibit improved properties compared to their pure metal counterparts. These improvements include:

• Increased Hardness: Alloys are generally harder than the pure metals they are made from.
• Increased Strength: Alloys are typically stronger and more resistant to deformation than pure metals.
• Improved Corrosion Resistance: Some alloys are more resistant to rusting or corrosion than the pure metals.
• Higher Melting Point: The melting point of an alloy is often higher than that of the pure metals that make it up.
• Improved Ductility and Malleability: In some cases, alloying can improve a metal's ability to be drawn into wires (ductility) or hammered into shapes (malleability).

Examples of Alloys and their Uses

Here's a table showing some common alloys and their applications:

Alloy	Composition	Properties	Uses
Steel	Iron and Carbon (typically up to 2%)	Strong, hard, relatively inexpensive	Construction, vehicles, tools
Brass	Copper and Zinc	Harder and more durable than copper, corrosion resistant	Musical instruments, decorative items, plumbing fittings
Bronze	Copper and Tin	Harder and more resistant to corrosion than copper	Statues, bearings, tools, ship fittings
Stainless Steel	Iron, Chromium, and Nickel	Highly corrosion resistant, strong	Cutlery, surgical instruments, chemical processing equipment
Solder	Tin and Lead (historically, now often lead-free alternatives)	Low melting point, good electrical conductivity	Joining metal parts in electronics and plumbing

The specific properties of an alloy depend on the types and proportions of metals used in its composition.