微细颗粒对复合材料熔体表观粘度的影响

以微米或亚微米级颗粒做为复合材料的增强体可减小因大颗粒造成的应力集中等缺陷,从而有望提高复合材料的机械性能。利用高能超声制备了不同粒径(最小达0.5微米)Al₂O₃颗粒增强的锌基复合材料。通过比较半固态加压除气的试样在重熔前后的高度变化,建立了增强颗粒粒径与复合材料熔体表观粘度间的关系。结果表明,熔体表观粘度的增大并非界面反应物作用的结果,而颗粒细化所导致的粘滞力增加是复合材料熔体表观粘度增大的主要原因,随之引入的气体是另一个原因。 

EFFECT OF PARTICULATE ON THE APPARENT VISCOSITY OF COMPOSITE MELT

In order to obtain better mechanical properties, fine particles in several micron or submicron diameter were used as reinforcement to reduce stress concentration usually induced by larger particles. Zn 22%Al matrix composites with alumina particulate reinforcement were fabricated by high intensity ultrasonic treatment. The diameters of particulates were different and the minimum one was 0.5 micron. Comparing the height changes of composites before and after remelt which have been degassed with semisolid compression, the relation between apparent viscosity and reinforcement diameter was obtained. Experiment results show that there is no interface reaction product involved in the apparent viscosity change. The smaller the particulate, the bigger the viscous force. That is the dominating reason for the composite melt apparent viscosity increment. And the gas introduced with particulate is another reason.