抄録
A method to uniformly distribute lead crystals throughout an aluminum alloy casting containing more than 5% of lead was developed. The wear characteristics of Al-(5∼15)% Pb-(1, 5)% Cu alloy prepared by the method were examined by rubbing on iron and steel under dry sliding conditions. Though in the Al-Pb system two phases appear in a wide composition range even in the liquid state, granular lead crystals are distributed uniformly when the melt heated up to a temperature above the solubility curve of the two liquid phases is thoroughly stirred and cast at a sufficiently high solidification rate. The lead crystals become larger with increasing pouring temperature. The lead content must be greater than 15% and the size of the lead crystals must be larger than 100μm in order to obtain an aged Al-Pb-5% Cu alloy with good wear resistance. Such alloys markedly excel in wear resistance under low sliding speed and high contact pressure. Annealed Al-Pb-1% Cu alloys are superior to aged Al-Pb-5% Cu alloys in wear resistance under light loads but are likely to cause seizure. A little wear of iron and steel is observed when rubbing with the Al-Pb-Cu alloys; this is particularly remarkable on cast iron, making severe wear and running-in wear disappear.
