机械搅拌器对C-SiC/Cu半固态浆料中石墨颗粒和SiCP的影响

利用直桨叶搅拌器在圆柱坩埚内机械搅拌C-SiC/Cu半固态浆料，研究搅拌速度为200 r/min、搅拌器上下移动速度为10 mm/s时C-SiC/Cu半固态浆料中石墨颗粒和SiC颗粒(SiC_P)的均匀性。结果表明:直桨叶与水平面的夹角γ与两种颗粒在坩埚顶部和底部含量偏差都存在二次关系，当γ=30°时石墨颗粒和SiC_P在坩埚中轴向分布均匀，但同一水平面内的SiC_P仍存在偏聚现象，说明SiC_P的偏聚是导致常规直桨叶机械搅拌C-SiC/Cu半固态浆料整体不均匀的主要原因；利用双层桨叶搅拌器代替常规直桨叶搅拌器，通过调整叶片层间距h，当h=10~20 mm时可以消除SiC_P的偏聚现象；通过对单层桨叶搅拌器和双层桨叶搅拌器机械搅拌铸造获得的C-SiC/Cu复合材料进行磨损试验发现，单层桨叶搅拌器不同部位磨损率存在差异，双层桨叶搅拌器磨损率几乎相同。说明SiC_P的偏聚可以通过增大机械搅拌剪切力度得以消除，利用双层桨叶搅拌器进行机械搅拌可以获得均质的C-SiC/Cu半固态浆料。 

Effect of mechanical stirrer on graphite particles and SiCP in C-SiC/Cu semi-solid slurry

The mechanical stirring of C-SiC/Cu semi-solid slurry was conducted in a cylindrical crucible by a straight-blade stirrer. The distribution of graphite particles and SiC particles (SiC_P) in the C-SiC/Cu semi-solid slurry was studied under 200 r/min for stirring speed and 10 mm/s for speed of moving up and down of stirrer. The results show that there is a quadratic relationship between the angle γ between the straight blade and the horizontal plane and the content of the graphite particles and SiC_P in the top and bottom of the crucible. When γ=30°, the axial distributions in the crucible of graphite particles and SiC_P are homogeneous, but the SiC_P are still segregated, which indicates that the segregation of SiC_P leads to the unhomogeneity of C-SiC/Cu semi-solid slurry in conventional straight-blade mechanical stirring. The double-blade agitator is used instead of the conventional straight blade agitator to adjust the blade layer spacing h to 10–20 mm, which can eliminate the segregation of SiC_P. The wear tests of the C-SiC/Cu composites obtained by mechanical stirring casting with single blade stirrer and double-layer blade stirrer were carried out. The wear rates of different parts of C-SiC/Cu composites in the single blade mechanical stirring casting are different, however, they are nearly the same in the double-layer blade. It shows that the segregation of SiC_P can be eliminated by increasing the mechanical agitation shearing action. The uniform distribution of C-SiC/Cu semi-solid slurry can be achieved by double-layer-stirrer mechanical stirring.