Question

Gun metal is an alloy of

• A. Cu - Sn
• B. Cu - Zn
• C. Al - Cu
• D. Al - Mn

Hint:

To easily distinguish common copper alloys:

• Copper + Tin = Bronze

• Copper + Zinc = Brass
Gunmetal is a well-known type of bronze.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Gunmetal is a specific type of bronze alloy. We need to identify its primary constituent elements from the given options.

Step 2: Detailed Explanation:
Let's define the alloys listed:

• Cu - Sn (Copper - Tin): These are the primary elements of

bronze.

• Cu - Zn (Copper - Zinc): These are the primary elements of

brass.

• Al - Cu (Aluminum - Copper): These are the primary elements of a class of high-strength aluminum alloys, such as Duralumin.

• Al - Mn (Aluminum - Manganese): These are the primary elements of a class of non-heat-treatable, corrosion-resistant aluminum alloys.

Gunmetal is a type of bronze. A classic composition for gunmetal (specifically red brass in some classifications) is 88% Copper, 10% Tin, and 2% Zinc (C83600 or LG2). The primary alloying element added to copper is tin, which makes it a bronze. The zinc is added as a deoxidizer and to improve casting properties.
Since the main components are Copper and Tin, the best classification among the choices is Cu-Sn.

Step 3: Final Answer:
Gunmetal is a type of bronze, which is primarily an alloy of Copper (Cu) and Tin (Sn).