变质工艺对复合铝合金钎焊层Si的形貌及尺寸的影响

4045铝合金铸造过程中分别采用Na盐、Al-Sr中间合金、Al-P中间合金等不同的变质剂进行变质处理，检测并分析了铸造组织中的初晶Si、共晶Si以及复合铝合金钎焊层Si的形貌与尺寸。结果显示，经Al-Sr中间合金变质处理的铸造组织中没有块状初晶Si，且共晶Si为球化的短棒状。对复合铝合金钎焊层的形貌进行检测发现，经变质处理的试样中Si颗粒发生球化且呈短棒状，未发现大的块状Si颗粒；而未经变质处理的试样中有明显的呈长条状的Si颗粒，且平均最大Feret直径、平均最小Feret直径、平均颗粒面积、颗粒总面积、颗粒面积分数等较大。表明Al-Sr中间合金变质剂对高硅铝合金铸造组织中的Si相以及复合铝合金钎焊层Si颗粒的形貌与尺寸有明显改善作用。

Influence of modification process on morphology and size of Si in brazing layer of cladding Al alloy

In the casting process of 4045 Al alloy, different modifiers such as Na salt, Al-Sr intermediate alloy and Al-P master alloy were used for modification. The morphology and size of primary Si, eutectic Si in the casting structure and Si particles in the brazing layer of cladding Al alloy were measured and analyzed. The results show that there is no bulk primary Si in the casting structure modified by Al-Sr intermediate alloy, and the eutectic Si is spheroidized short rod. By detecting the morphology of the brazed layer of the cladding Al alloy, it is found that the Si particles in the modified sample are spheroidized and in the shape of short rods, and large bulk Si particles are hardly found. However, in the sample without modification, there are obvious elongated Si particles, and the average maximum Ferret diameter, the average minimum Ferret diameter, the average particle area, the total particle area, and the percentage of particle area are larger. It indicates that the Al-Sr intermediate alloy modifier can significantly optimize the morphology and size of the Si phase in the casting structure of the high-Si Al alloy and the Si particles in the brazing layer of the cladding Al.