High-temperature behaviour — duralumin vs Y-alloy: Assess the statement: “Duralumin has better strength than Y-alloy at high temperature.”

Introduction / Context:Duralumin (Al–Cu–Mg wrought alloy) is optimized for room-temperature to moderately elevated temperatures, whereas Y-alloy (Al–Cu–Ni–Mg casting alloy) was designed specifically to retain strength at higher temperatures. Understanding this distinction informs material selection for engine parts and hot-service components.

Given Data / Assumptions:

• Duralumin typically contains copper and magnesium with minor manganese.
• Y-alloy contains copper and nickel with minor additions for hot strength and stability.
• Comparison is at elevated service temperatures typical of engine environments.

Concept / Approach:Nickel in Y-alloy stabilizes strengthening phases and improves creep resistance and hot strength, allowing Y-alloy to outperform duralumin as temperature increases. Duralumin suffers greater overaging and softening at high temperature. Therefore the statement that duralumin has better high-temperature strength than Y-alloy is incorrect.

Step-by-Step Solution:Identify alloy families: duralumin (wrought), Y-alloy (casting).Relate alloying to performance: Ni in Y-alloy enhances high-temperature strength retention.Compare softening behavior: duralumin loses strength more rapidly with temperature.Conclude the statement is false.

Verification / Alternative check:Handbook property charts show better tensile and creep strength for Y-alloy at elevated temperatures compared with duralumin.

Why Other Options Are Wrong:Any qualified “True” options contradict the documented superiority of Y-alloy at high temperature.

Removing copper makes no sense in this context; copper contributes to precipitation hardening in both systems.

Common Pitfalls:Assuming a stronger room-temperature alloy remains stronger at high temperature without considering overaging and phase stability.

Final Answer:False