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利用单辊旋淬快速凝固法制备Al-21Si和Al-30Si过共晶铝硅合金,采用扫描电镜、透射电镜及XRD技术对所制备合金的组织形貌和相结构进行表征.结果表明:快速凝固合金形成微纳米晶组织,晶粒明显细化.Al-21Si过共晶合金凝固组织由羽毛针状(α-Al+β-Si)共晶体和雪花状α-Al相组成;快速凝固有效抑制初生硅相的形核与生长,α-Al相领先共晶形核生长,形成微纳米级亚共晶组织.Al-30Si高硅过共晶合金初生硅相细小钝化,初晶Si相显微结构为孪晶形貌,呈典型的过共晶组织特征.快速凝固显著提高了合金的显微度和耐磨性,快速凝固Al-21Si合金的耐磨性是传统铸造合金的5倍.
The Al-21Si and Al-30Si hypereutectic Al-Si alloys were prepared by single-roll rapid quenching and the morphology and phase structure of Al-21Si and Al-30Si alloys were characterized by scanning electron microscopy, transmission electron microscopy and X-ray diffraction The solidified alloy formed micro-nanocrystalline microstructure and the grain was obviously refined.The solidified microstructure of Al-21Si hypereutectic alloy consisted of feather acicular (α-Al + β-Si) eutectic and snowflake-like α-Al phase. Inhibit the nucleation and growth of primary silicon phase, α-Al phase leading eutectic nucleation growth, the formation of micro-nano-scale hypoeutectic microstructure .Al-30Si high silicon hypereutectic alloy primary silicon phase small passivation, primary Si phase Microstructure is twins morphology, showing the typical hypereutectic microstructure.The rapid solidification significantly improves the microstructure and wear resistance of the alloy, the wear resistance of rapidly solidified Al-21Si alloy is 5 times that of the traditional cast alloy.