Question

The alloy of copper which can be used against fatigue, wear and corrosion is

• A. Phosphorous bronze
• B. Beryllium bronze
• C. Aluminum bronze
• D. Cartridge bronze

Hint:

When selecting an alloy for demanding applications like those involving fatigue, wear, and corrosion, understanding the specific properties imparted by alloying elements is crucial. Beryllium bronze is renowned for its unique combination of high strength, elasticity, and resistance to fatigue and corrosion, making it a preferred choice for such challenging environments.

Answer 1

The Correct Option is B

Step 1: Understand the properties required (fatigue, wear, and corrosion resistance).
The question asks for a copper alloy that exhibits high resistance to fatigue, wear, and corrosion.
Step 2: Evaluate the properties of each option.
(1) Phosphorous bronze: This alloy of copper with tin and phosphorus is known for its strength, toughness, good corrosion resistance, and excellent wear resistance. It's often used in bearings and gears. While it offers good wear and corrosion resistance, its fatigue resistance is generally not as outstanding as beryllium bronze. (2) Beryllium bronze (Copper Beryllium): This alloy of copper with beryllium (typically 0.5% to 3% beryllium) is known for its exceptional strength, hardness, and elasticity. It can be heat-treated to achieve very high mechanical properties. Crucially, it combines high fatigue strength, excellent wear resistance, and good corrosion resistance, particularly in various environments including seawater. These properties make it suitable for springs, electrical connectors, non-sparking tools, and components subjected to repeated stress. (3) Aluminum bronze: This alloy of copper with aluminum (typically 5% to 11% aluminum) is known for its high strength, good corrosion resistance (especially in marine environments), and excellent wear resistance. It forms a durable, self-healing oxide layer. While strong and corrosion-resistant, its fatigue properties are generally not superior to beryllium bronze for applications specifically requiring high fatigue resistance. (4) Cartridge bronze (Brass): This is essentially an alpha brass, an alloy of copper and zinc (typically 70% copper, 30% zinc). It has good ductility, strength, and workability. It's commonly used for cartridge cases (hence the name), pipes, and architectural metalwork. While it has decent corrosion resistance, it is generally inferior to the other bronze alloys in terms of strength, fatigue resistance, and wear resistance.
Step 3: Conclude based on the properties.
Beryllium bronze stands out due to its superior combination of high strength, excellent fatigue resistance, good wear resistance, and corrosion resistance among the listed options. The final answer is $\boxed{\text{2}}$.