| Summary: | The present study examines the effect of trace additions of copper (up to 1 wt.%) and zinc (0.5 wt.%) as the alloying elements on the microstructure, hardness, and wear behaviour of T6 treated A356 (Al-7Si) alloy. Wear tests were conducted using a pin-on-disc tribometer under a constant sliding speed of 200 RPM, varying applied load (20–40 N), and sliding distance (0–3000 m) to determine the wear rate and the coefficient of friction. The results indicated a minimum of 1 wt.% of copper was required to form the Al<sub>2</sub>Cu intermetallic phase, resulting in a finer grain structure and improved hardness. However, the role of zinc as a trace element was not observed on the microstructure; the observed changes may be the combined effect of copper and zinc as a whole. The highest hardness of 107 VHN (98% increase) was achieved with 1 wt.% copper addition during peak aging at 100 °C. Also, wear tests showed that adding 1 wt.% copper to the A356 alloy and a 100 °C precipitation hardening (T6) treatment improved the wear resistance by 150–182% with a reduced coefficient of friction.
|
|---|