压力和超声波作用下铝合金中富铁相的形成特点及其对合金力学性能的影响

Iron is thought to be a very harmful impurity element and difficult to remove in aluminum alloys, which will accumulate in recycled aluminum alloys. It is critical to control the detriment of the Fe-rich intermetallic phases in order to improve the energy saving, emission reduction and high efficient utilization of resources in aluminum industry. In this proposal, the Al-Cu-based alloys with high iron contents will be investigated by combining the ultrasonic treatment, the squeeze casting processing and the nutralization of the Fe-rich intermetallic phases. The attempt focuses on the formation of the Fe-rich intermetallic phases and its effects on the mechanical propterty of the alloys. Based on this study, The type of the Fe-rich intermetallic phases, the solidification sequences and the solidification reactions in Al-Cu-based alloys will be clarified. Furthermore, the solidification characteristics of the Fe-rich intermetallic phases in Al-Cu-based alloys coupled by ultrasonic treatment and squeeze casting and its effects on the mechnical property of the alloys will be revealed. Finally, the achievement of the project is helpful for the development of the high performance low cost aluminum alloys and the promotion of high efficient utilization of reclyced aluminum alloys and it is also available for green casting.

铁是铝合金中难以避免且对合金性能危害很大的杂质元素，废铝回收时铁还会不断累积，控制富铁相的危害是铝合金生产过程中实现节能减排、资源循环高效利用的关键环节。本项目以高铁含量Al-Cu合金为研究对象，将挤压铸造技术、超声处理技术与中和变质处理技术相结合，分析合金中富铁相的形成特点及其对合金力学性能的影响。通过本项目研究，将明晰铝铜合金中富铁相类型、凝固顺序和相变反应，阐明超声处理和挤压铸造耦合作用过程中富铁相的形成特点，揭示富铁相对高铁含量Al-Cu合金力学性能影响的规律。本项目研究对开发高性能、低成本铝合金新材料，推动铝再生及其高效利用，实现绿色铸造有着重要的促进作用。

铸造Al-Cu合金广泛应用于建筑、电子、机械制造、航空航天和石油化工等各个工业部门。项目将超声处理、挤压铸造和中和变质处理有效结合，揭示了富铁相的形成机制及其对合金力学性能的作用机制，可有效改善Fe元素在铝铜合金中的不利影响。主要进展是设计了一种具有自主知识产权的基于功率超声与压力耦合的挤压铸造方法及装置，并在此基础上研究了在不同超声处理工艺和挤压铸造工艺中富铁相的三维形貌、形成特点及室温和高温力学性能。明晰了富铁相在超声处理和挤压铸造过程中的凝固顺序和相变反应；结合中和变质处理技术，研究了Si、Mn等元素在富铁相形成过程中的作用；研究了富铁相类型和形貌特征对合金断裂行为的影响，分析合金中除富铁相外的其他第二相和组织缺陷等对合金力学性能的影响。本项目的完成深化了对金属材料凝固规律的认识，并为推动高性能铝合金发展中的节能环保和铝合金废料的高效回收利用，实现绿色铸造提供了理论依据和关键技术。