Alloys are preferred to pure metals for several reasons:
1. Improved Mechanical Properties:
- Alloys combine the properties of different elements to enhance strength, hardness, toughness, and ductility.
- For example, steel, an alloy of iron and carbon, is stronger and harder than pure iron.
2. Corrosion Resistance:
- Some alloys are more resistant to corrosion than their pure metal components.
- For example, stainless steel (an alloy of iron, chromium, and nickel) is highly resistant to rust.
3. Electrical and Thermal Conductivity:
- Alloys can be designed to have specific electrical and thermal conductivity values.
- For example, bronze (an alloy of copper and tin) has higher electrical conductivity than pure copper.
4. Specific Properties for Applications:
- Alloys can be tailored to meet specific requirements for particular applications.
- For example, shape memory alloys (SMAs), which recover their original shape upon heating, are used in aerospace and medical devices.
5. Lower Cost:
- In some cases, alloys can be more cost-effective than pure metals.
- This is because they may contain less expensive elements or require less processing.
6. Improved Machinability:
- Alloys can be designed to improve their machinability, making them easier to shape and work with.
- For example, free-machining steels contain additives that reduce friction and improve chip formation during cutting.
7. Magnetic Properties:
- Alloys can be designed to have specific magnetic properties, such as magnetism or non-magnetism.
- For example, alnico (an alloy of iron, nickel, and aluminum) is used in permanent magnets.
8. Improved Wear Resistance:
- Some alloys, such as Stellite (an alloy of cobalt, chromium, and tungsten), exhibit high wear resistance.
- This makes them suitable for applications involving friction and abrasion.