电磁离心铸造初晶Si与Mg2Si颗粒互补增强铝基梯度功能复合材料气缸套的应用基础研究

传统铁质气缸套具有密度大、与铝合金缸体匹配性差的缺点，长期使用会导致漏油、漏气、能效降低等噬待解决的难题，而已见报道的新型铝合金气缸套，却工艺复杂、成本高，不利于广泛推广。针对这些问题，项目提出了电磁离心铸造制备初晶Si与MgSi颗粒互补增强铝基梯度功能复合材料气缸套的新思路。该思路以Al-Si-Mg三元合金为毛坯材料，利用电磁离心复合场对晶粒的分离、细化功能将合金中两种具有互补性质的初晶相有机揉合在一起，形成局部具有高体积分数初晶颗粒的铝基梯度功能复合材料。依此思路，项目首先对复合场作用下初晶颗粒的细化机制与分布特征进行深入研究，然后，拟通过对电磁场强度、离心转速、电磁离心复合场的匹配关系和合金成分的调整实现梯度功能复合材料微观组织和性能的设计与控制；进一步通过热处理制度的研究和微量合金元素的添加，实现复合材料性能的优化（尤其是高温性能的改善），为其替代铁质气缸套的工业应用奠定基础。

The traditional iron cylinder is characterized by high density and poor matching with Aluminum alloy cylinder block. Long-term use of it may lead to oil spilling, gas spilling and the reduction of energy efficiency, which demands prompt solution. However, the latest Aluminum alloy cylinder which has been reported is prepared with complex technology and high cost, which is not easy to promote widely. This project thus proposes a new way to prepare cylinder with Al-based functional gradient composites reinforced by complementary primary Si and Mg2Si particles under electromagnetic centrifugal force. The preparation takes the ternary Al-Si-Mg alloys as blank materials. It organically mixes the two sorts of complementary primary phase in the alloy by making use of electromagnetic centrifugal composite field's separating and refining function, forming Al-based functional gradient composites, part of which consists of high-volume fraction primary particles. Therefore, for a start, the project is to study intensively primary particles' refining mechanism and distributing characteristics in the composite field; after that, it is to fulfill the design and control of functional gradient composites' microstructure and property by adjusting the matching relations of electromagnetic intensity, centrifugal rotating speed and electromagnetic centrifugal composite force as well as alloy components; furthermore, through study of heat treatment and adding minor alloying elements, the project is to complete the optimization of composites' property (especially the improvement of high temperature property) and lay the foundations for its replacement of iron cylinder in industrial application.