原位纳米颗粒孕育亚共晶Al-Si-Mg合金的微观组织演变规律及作用机制

Al-Si-Mg合金广泛应用在形状复杂的薄壁零件、航空工业承受高静载荷的零件、汽车工业中的气缸体和气缸盖等方面。为了满足现代工业对铝合金更高的使用要求，通常对铝合金进行孕育或变质处理后使用。然而，当Si含量大于4wt.%时进行Al-Ti-B和Al-Ti-C中间合金孕育处理，Ti元素会与Si元素发生反应而产生毒化作用，并且稀土变质会增加成本。近来，我们发现了一种原位形成纳米颗粒孕育铝合金的新途径，因此，本研究采用FeBSi非晶合金为载体，亚共晶Al-Si-Mg合金为基体合金，揭示出原位纳米颗粒孕育对α-Al枝晶、共晶硅和纳米析出相的影响规律及机制，以及微观组织与室温、高温力学性能的影响规律和机制。本研究可以扩宽非晶的应用范围，丰富和发展孕育理论，开发高性能的新型孕育剂，实现Al-Si-Mg合金的组织可控，为开发高性能铝合金提供重要的数据支持和理论基础。

Al-Si-Mg alloy is widely used in complex thin-walled parts, aviation industry bearing parts of high static load, cylinder block and cylinder head in automotive industry. In order to meet the higher requirements of modern industry for aluminum alloy, the aluminum alloy is usually used after inoculation or modification. However, when Si content is higher than 4wt.%, Ti elements in Al-Ti-B and Al-Ti-C master alloys react with Si elements to come out poisonous effect, and rare earth modification will increase the cost. Recently, we have found a new approach of in situ formation of nano-particles to inoculate Al Alloy. Therefore, this study adopts FeBSi amorphous alloy as the carrier, hypoeutectic Al-Si-Mg alloy as matrix alloy, reveal the influence law and mechanism the of in situ nano-particles on the α-Al dendrite and eutectic silicon and nano-precipitates, the influence law and mechanism of microstructure and mechanical properties at high temperature and room temperature. This research can widen the application scope of metallic glass, enrich and develop the inoculation theory, develop high-performance new inoculant, realize the controllable microstructure of Al-Si-Mg alloy, and provide important data support and theoretical basis for developing high-performance aluminum alloys.