Duralumin consists of aluminum, copper?

Analysis

The question asks for the composition of the alloy Duralumin. To answer this, we need to identify the specific metals that are combined with aluminum and copper to form this lightweight, high-strength alloy.

Concept

An alloy is a mixture of two or more elements, where at least one is a metal. Duralumin is a well-known alloy used extensively in the aircraft industry because it is strong, lightweight, and resistant to corrosion.

The standard composition of Duralumin is:

• Aluminum (Al): Approximately 90–95% (the base metal)
• Copper (Cu): Approximately 4%
• Magnesium (Mg): Approximately 0.5–1%
• Manganese (Mn): Approximately 0.5%

Step-by-Step Solution

1. Identify the base: We know Duralumin is an aluminum-based alloy.
2. Recall the additives: While aluminum and copper are the primary components, the specific properties of Duralumin (like its hardness and heat-treatability) are achieved by adding small amounts of Magnesium and Manganese.
3. Evaluate the options: • Option A (Zinc and Gold): Incorrect; these are not standard components of Duralumin. • Option B (Lead and Manganese): Incorrect; Lead is not a component. • Option C (Nickel and Silver): Incorrect; these are not components. • Option D (Manganese and Magnesium): Correct; these are the two essential trace elements added to the aluminum-copper base.

Conclusion

Based on the standard chemical composition of Duralumin, the correct components are Aluminum, Copper, Manganese, and Magnesium.

Exam Tip

To remember the composition of Duralumin, use the mnemonic "Dura-M&M":

• Dura (Duralumin)
• M (Manganese)
• &
• M (Magnesium) This helps you quickly associate the alloy with the two "M" metals!