The apparent viscosity of fine particle reinforced composite melt

In order to obtain better mechanical properties, fine particles in several micron or submicron diameter are used as reinforcement to reduce stress concentration which are usually induced by larger particles. Zn–22% Al matrix composites with fine alumina particulate reinforcement are fabricated by high intensity ultrasonic treatment. The particulate sizes are chosen with the minimum 0.5 μm. Comparing the height change of composite samples before and after remelted, which have been degassed with semisolid compression, the relation between apparent viscosity and reinforcement diameter is obtained. Experimental results show that there is no interface reactive product involved in the apparent viscosity change. With smaller particulate size, the viscous force is enhanced. That is the dominating reason for the composite melt apparent viscosity increment. An additional reason is the gas introduced with the particulates.