Wear behaviour of eutectic and hypereutectic Al–Si–Cu–Mg casting alloys tested against a composite brake pad

The wear resistance of nine eutectic and hypereutectic Al–Si alloys with various compositions and processing routes was studied. Testing was conducted using a pin-on-disc configuration and two different testing speeds. At lower disc speed, the influence of the composition and alloy processing was very strong and a severe wear transition was observed for the alloys with low fractions of primary silicon particles. At higher disc speed, wear of all the alloys but one was very low. The high wear alloy had a high silicon content and a very large primary silicon size; the accelerated wear was caused by cracking and fracture of the large silicon particles upon impact with the abrasive disc material at the higher speed.