Sr-PM复合变质过共晶铝硅合金

Modification of Al-Si Hypereutectic Alloys by Sr-PM

研究了PM和Al -10Sr复合变质过共晶铝硅合金A3 90。考察了复合变质剂的加入顺序、加入量以及变质的长效性。试验发现:PM和Sr复合变质剂的加入顺序对过共晶铝硅合金A3- 90变质效果影响很大,先加入PM变质剂,后加入Sr变质剂,变质后初晶硅呈现开花状形貌,共晶硅为细小的圆点状;先加入Sr变质剂,后加入PM变质剂,初晶硅变质效果明显优于单独PM变质效果。加入PM质量分数为1%时,Al -10Sr变质剂的最佳加入量为合金质量的0 .4% ,变质后初晶硅平均尺寸可达到3 5 μm ,而且PM与Sr复合变质具有很好的长效性。

Modification of hypereutectic Al-Si alloy by Sr and PM was conducted.The addition sequence,addition and long effectiveness of the compound modifier were investigated.The results show that addition sequence of the compound modifier obviously affects the dimension of Si phase.Adding PM modifier before adding Al-Sr master alloy,the shape of primary silicon is rosset-like in which the fine round-point eutectic silicon appears in the aluminum alloy.On the contrary,the dimension of the primary silicon in A390 alloy is obviously smaller than that of the modified alloy with single PM modifier.The average size of the primary silicon can be reduced to 35μm with modification of 1%PM addition and 0.4% of the alloy weight for Al-10Sr master alloy addition.Moreover,the PM and Sr compound modification has a better long effectiveness.