Al–Si piston alloys and casting method: Assess the statement: “An aluminium alloy containing approximately 11% silicon is used for manufacturing engine pistons by the die-casting process.”

Introduction / Context:
Aluminium–silicon (Al–Si) alloys are staple materials for automotive pistons due to their castability, low density, reasonable strength, and good wear resistance. Silicon content around the eutectic range confers fluidity and low shrinkage, enabling complex shapes in casting.

Given Data / Assumptions:

• Silicon content ~11%, which is near the Al–Si eutectic range (~11–13%).
• Manufacturing route: die casting (pressure die casting or gravity die casting depending on design).
• Piston application demands dimensional stability, wear resistance, and good thermal conductivity.

Concept / Approach:
Near-eutectic Al–Si alloys exhibit excellent fluidity and feed thin sections well, which suits die-cast piston crowns and skirts. Silicon particles improve scuff resistance and reduce thermal expansion. Many piston alloys also incorporate small amounts of Cu, Ni, or Mg for strength at temperature, but the base premise of using ~11% Si is correct.

Step-by-Step Solution:
Relate required properties (wear, castability) to the Al–Si system.Note that ~11% Si aligns with eutectic composition, promoting sound die castings.Acknowledge optional alloying (Cu, Ni, Mg) without negating the core statement.Conclude: the statement is correct.

Verification / Alternative check:
Automotive materials data commonly list eutectic or hypereutectic Al–Si alloys (about 11–18% Si) for pistons, via gravity or pressure die casting.

Why Other Options Are Wrong:
“No” and variants contradict well-established practice; saying pistons avoid silicon is incorrect; limiting to sand casting ignores industry die-casting routes for certain piston designs.

Common Pitfalls:
Confusing die casting with forging routes used for high-performance pistons; both exist, but Al–Si die-cast pistons are widespread in mass production.

Final Answer:
Yes