利用几何优化的搅拌设备改善半固态搅拌法制备的B_4C_p/A356复合材料的颗粒分布均匀性

Improving Particle Distribution Uniformity of the Semisolid-state-stirring Prepared B_4C_p/A356 Composites by Applying a Geometrically Optimized Stirring Apparatus

本工作旨在验证几何优化的搅拌设备对半固态搅拌法制备的B_4C_p/A356复合材料颗粒分布均匀性的改善效果。通过建立几何参数优化后的搅拌设备模型,用FLUENT软件模拟和分析了半固态搅拌法(SSSM)制备的B_4C_p/A356的流场,并分别用普通搅拌设备和优化的搅拌设备制备出B_4C_p/A356铝锭,然后从宏观与微观的角度分析了B_4C颗粒的分散效果。模拟与分析结果表明:优化后的搅拌设备在半固态铝液(SSAL)中搅拌时,能够产生促进B_4C颗粒分散的三层非等速交汇涡流;桨叶倾斜角为60°的二层对推正交式搅拌桨增大了桨叶与半固态铝液的接触面积,且使下层铝液中的B_4C颗粒分布更为均匀。

The present work aimed to evaluate the performance of a geometrically optimized stirring apparatus designed for the semisolid state stirring preparation of particle-reinforced aluminum matrix composite,from the perspective of improving particle distribution uniformity.We simulated the flow field of the material system during the semisolid state stirring of B 4C p/A356 composite by using the FLUENT software while applying the stirring apparatus model with the optimized geometric parameters.We then prepared B 4C p/A356 aluminum ingots using ordinary stirring apparatus and geometrically optimized stirring apparatus,respectively,and analyzed both macroscopically and microscopically the distribution of B 4C particles in the matrices.The simulation and analysis results showed that the geometrically optimized stirring apparatus can generate an inconstant velocity intersect vortex beneficial to the dispersion of B4C particles when agitates in the semisolid state aluminum liquid(SSAL).The dual-layer pair-pushing orthogonal paddle with a blade tilt angle of 60°leads to a larger contact area between the blade and the SSAL,and in consequence,contributes to more uniform distribution of B 4C particles in the lower part of aluminum matrix.