复杂曲面铝合金件铸锻复合成形过程材料流动行为与微观组织演化机制

随着汽车制造业快速发展，对结构轻量化及节能减排提出了更高要求，亟需轻质金属材料，特别是铝合金的先进制造方法。本项目针对复杂曲面铝合金件锻造工艺路线长、机加量大、成本高，以及铸造力学性能低等问题，提出了一种铝合金铸锻复合成形新工艺，该工艺在一套模具内先后完成零件的铸造及局部区域的锻造成形，从而改善材料微观组织并提高力学性能，是一种短流程、低能耗制造工艺。项目拟通过理论分析、数值模拟和试验研究的方法对A356铝合金铸锻复合成形中材料变形机理及组织演变规律进行深入研究。建立铸造过程中缩松分布预测模型及锻造过程中微观孔洞闭合判据；揭示铸锻复合成形过程中晶粒细化机制，并建立再结晶模型；获得成形模具结构及冷却流道排布优化设计方法；探究成形参数对结构件力学性能的影响规律，并最终实现汽车铝合金控制臂零件的铸锻复合成形，成形件关键部位力学性能达到锻件性能指标。项目的研究可促进铝合金在汽车底盘结构件中的应用。

With the rapid development of the automobile manufacturing industry, higher requirements have been put forward for lighter structures, energy-saving and emission reduction. There is an urgent need for lightweight metal materials, especially advanced manufacturing methods for aluminum alloys. This project aims to solve the problems of long forging process routes for complex curved aluminum alloy parts, large amount of machining, high cost, and low casting mechanical properties, and proposes a new aluminum alloy casting and forging complex forming process. The casting of the parts and the forging of the local area are completed in a set of molds, thereby improving the microstructure of the material and improving the mechanical properties. It is a short process and low energy consumption manufacturing process. The project intends to conduct in-depth research on the deformation mechanism and microstructure evolution of A356 aluminum alloy castings and forgings through theoretical analysis, numerical simulation and experimental research methods: 1)establishing the prediction model of shrinkage distribution in the casting process and the microscopic hole closure criteria in the forging process, 2)revealing the grain refinement mechanism in the forging and forging complex forming process, and establish the recrystallization model, 3)obtaining the forming die structure and optimizing the cooling runner arrangement. The research of the project can promote the application of aluminum alloy in automotive chassis structural parts.