基于 Anycasting 的铝硅合金离心铸造数值分析

针对采用离心铸造方法制备自生初晶颗粒增强的铝基梯度复合材料过程中产生的宏观缺陷,以Anycasting为模拟软件,以Al-18Si-6Mg合金为研究对象,采用数值模拟和试验相结合的方式对卧式离心铸造的充型过程、温度场分布、卷气过程、氧化夹渣形成位置以及缩孔的形成进行了详细的分析.结果显示,针对该类铝合金,离心转速控制在1 000r/min左右时,铸件可以获得较好的外观形貌;同时,成型过程中的卷气是导致铸件形成气孔的主要原因.气孔与氧化夹渣的分布位置与充型过程、温度场分布以及铸型结构有关.而铸件轴向和壁厚方向上的双向凝固是造成缩孔的关键,如何解决成形过程中的双向凝固,是采用离心铸造制备自生增强铝基梯度复合材料有待解决的关键难题.

An Anycasting-Based Numerical Simulation of Centrifugal Casting of Al-Si Alloy

Taking into account the macroscopic defects occurring in the process of preparing in-situ primary particle-reinforced Al gradient composites, the authors took Al-18Si-6Mg alloys as the object of study and Anycasting as the simulation software, and used numerical simulation in combination with experiment to analyze in detail the filling process, the temperature field distribution, gas involving, the position of oxide inclusion formation and the formation of shrinkage cavities in the process of horizontal centrifugal casting. The results showed that the casting gave a satisfactory appearance at the speed of 1000 r/min for this kind of aluminum alloy and that the volume of gas in the molding process was the main cause for the formation of pores in the casting. The distribution of pores and oxide inclusions was shown to be related to the filling process, the temperature field distribution and the structure of the mould. Bidirectional solidification in the axial and thickness directions was the key factor of shrinkage formation. In conclusion, how to solve the problem of bidirectional solidification will be the hard nut to crack for preparing in-situ primary particle-reinforced Al gradient composites through centrifugal casting.