Alloy identification — what is bronze? Bronze is correctly defined as which of the following alloy systems?

Introduction / Context:
Bronze and brass are two historically important copper alloys with distinct base systems. Correctly identifying these alloys is vital for selecting materials with appropriate mechanical properties, corrosion resistance, and casting behavior in engineering applications.

Given Data / Assumptions:

• Bronze traditionally refers to copper–tin alloys.
• Brass refers to copper–zinc alloys.
• Modern marketing sometimes broadens “bronze” to include other copper-based alloys (e.g., aluminium bronze), but classical metallurgical usage is copper–tin.

Concept / Approach:
In standard metallurgical terminology, bronze = Cu–Sn, and brass = Cu–Zn. While there are variants like phosphor bronze (Cu–Sn–P) and aluminium bronze (Cu–Al), the foundational identification for “bronze” in basic materials questions remains copper and tin. This distinction correlates with differences in strength, wear resistance, and corrosion behavior.

Step-by-Step Solution:
Match “bronze” to copper–tin system.Exclude copper–zinc (brass) and multi-component mixtures that are not the canonical bronze.Therefore, select “Copper and tin”.Note that specialised bronzes may include minor additions (e.g., P) but remain Cu–Sn based.

Verification / Alternative check:
Property tables list typical bronzes (e.g., tin bronzes) with Sn ~ 3–12% for bearings and springs, confirming Cu–Sn as the system.

Why Other Options Are Wrong:
(a) identifies brass. (c) is a ternary alloy that could exist but is not the standard definition of bronze. (e) refers to aluminium bronze, a specific subclass; the general textbook definition is Cu–Sn.

Common Pitfalls:
Relying on trade names that stretch “bronze” to many copper alloys; for exams, stick to the classical definition.

Final Answer:
Copper and tin