Hardness （HRB） and wear resistance as well as microstructure under different conditions were investigated on as-cast

solid solution and solid solution +aging centrifugal casting particle reinforced Al-20Si-5Mg composites cylinder liner

which were also comparatively analyzed with those of cast iron cylinder liner for automobile and motorcycle. The results show that average hardness of particle reinforced Al-20Si-5Mg composites cylinder liner is lower than that of cast iron ones. However

with increasing in loading

under dry sliding condition

wear resistance of the composites cylinder liner at as-cast

solid solution and solid solution +aging state is apparently superior to that of cast iron ones

while under wet condition

with high loading

such as 300N and 400N

it is slightly better than that of cast iron ones.