铺粉工艺对SiC颗粒增强铝基表面复合材料性能的影响

Influence of Powder Spreading Process on the Preparation of SiC Particle Reinforced Aluminum Matrix Surface Composite

搅拌法制备SiC颗粒增强铝基复合材料时铺粉工艺对材料性能影响很大,影响SiC颗粒能否均匀地嵌入基体中。研究黏接剂、SiC颗粒粒径、颗粒铺粉厚度等对搅拌摩擦制备SiC颗粒增强铝基复合材料的影响。以焊缝宏观质量、SiC颗粒体积分数与硬度、基体组织及颗粒、复合材料不同深度维氏硬度、复合区面积(宏观)为表征参量对制备的复合材料进行表征,并得出最佳的铺粉工艺。结果表明:相比于α-氰基丙烯酸乙酯,聚乙烯醇作为黏接剂时,复合材料中SiC颗粒的分布更加均匀;嵌入基体的SiC颗粒体积分数随着SiC粉末粒径的增加而增加,而基体中SiC颗粒体积分数相同情况下,SiC颗粒的粒径越小对基体材料硬度的提高越明显;复合材料中SiC颗粒增强区面积会随着铺粉厚度的增加而增加,但增加铺粉厚度会使得SiC颗粒增强区硬度、体积分数的变化梯度增加。

In the preparation of SiC particle reinforced aluminum matrix composite by friction stir method,the parameters of powder placement have a great influence on the properties of the material,and affect the uniform embedding of SiC particles in the matrix.The effects of binder,SiC particle size and powder spreading thickness on the preparation of SiC particle reinforced aluminum matrix composites by friction stir were studied.The macroscopical quality of the weld,the volume fraction and hardness of SiC particles,the matrix structure and particles,the Vickers hardness of different depths of the composite,and the area of the composite zone(macroscopical)were used as the characterization parameters to characterize the composite,and the best powder spreading process was obtained.Compared with the binder ofα-cyanoacrylate,when polyvinyl alcohol is used as binder,the distribution of SiC particles in the composites is more uniform.The volume fraction of SiC particles embedded in the matrix increases with the increase of SiC particle size,and when the volume fraction of SiC particles in the matrix is the same,the smaller the size of SiC particles,the more obvious the improvement of the matrix material hardness.The area of SiC particle reinforced zone in composites increases with the increase of powder spreading thickness,but the increase of powder spreading thickness will result in the increase of the gradient of hardness and volume fraction in the SiC particle reinforced zone.