共晶型Al-Si合金中(Ca_(n-x),Na_x)P_m化合物的形成与磷变质失效分析

FORMATION OF (Ca_(n_x), Na_x)P_m COMPOUNDS IN EUTECTIC Al-Si PISTON ALLOYS AND INVALIDATION OF PHOSPHORUS MODIFICATION EFFECT

利用金相和电子探针微量分析仪(EPMA)等手段研究了共晶型Al-si(ZL109)合金熔体中Ca或(和)Na对Al-P中间合金变质效果的影响、含磷化合物的组成与磷变质的关系,结果表明,合金中Ca或(和)Na能使磷变质失效,甚至出现反常的Na变质效果;Ca或(和)Na促使AlP分解,并与磷形成比AlP更稳定的(Ca_(n-x),Na_x)P_m化合物,从而抑制了磷变质作用的发挥;C_2Cl_6精炼可使(Ca_(n-x),Na_x)P_m化合物的组成和结构发生转化,形成了能作为初晶Si结晶核心的(Al_5,Mg_(0.85),Ca_(0.15))P_(3.4)化合物,从而使磷变质效果得以恢复。

The influence of Ca and Na on phosphorus modification performance, the relation between constitution of compounds containing-phosphorus and modification performance in eutectic Al-Si piston alloys were investigated by optical microscopy and electron probe microanalyzers (EPMA). It has been shown that Ca or (and) Na can make phosphorus modification inefficiency and even Na modification efficiency appears, the abnormal phenomena is due to the formation of (Can-x, Na-x)P-m compounds which is more stable than AIP phases in the melt. However, the phosphorus modification efficiency can recover after refining treatment by C2Cl6, because of (Can-x, Na-x)P-m changing to (Al-5, Mg-0.85, Ca-0.15) P-3.4 which can serve as the nuclei of primary Si phases.