与通常的变质结果相反,在活塞用共晶ZL108合金的铸造生产中,采用含磷熔剂处理液态合金,目的在于适当粗化共晶体,消除铸态组织中的α-Al初晶,代之以一定量的初晶硅晶体。这种过共晶型组织可明显地提高活塞的使用性能。 合金凝固时,随冷却速度增加,铸态金相组织也随之细化。例如,共晶铝硅合金的 Contrary to usual metamorphic results, the liquid alloy is treated with a phosphorus-containing flux in the production of a piston with a eutectic ZL108 alloy for the purpose of appropriately coarsening the eutectic and eliminating the α-Al primary crystal in the as-cast structure A certain amount of primary crystal silicon. This hypereutectic structure can significantly improve the performance of the piston. Alloy solidification, with the cooling rate increases, as cast microstructure also will be refined. For example, eutectic Al-Si alloy