Metallurgy: effect of silicon addition to copper Silicon is added to copper (silicon bronze) as an alloying element. Which property combination is most improved by silicon in copper alloys? Choose the correct option.

Given
Silicon is added to copper (forming silicon bronze) to modify properties.

Concept / Approach
Silicon in copper forms silicon bronzes noted for higher strength with good ductility and corrosion resistance. Machinability improvements in copper are more commonly associated with lead, sulfur, or tellurium additions, not silicon.

Option analysis
• Machinability: not the primary benefit of silicon in copper alloys.
• Hardness or hardness+strength: only partially reflects the effect; silicon bronzes maintain useful ductility.
• Strength and ductility: best describes silicon bronze performance.

Final Answer
Strength and ductility