Study On Preparation Technology Of SiC Particle Reinforced ZL702 Alloy

In this paper, we study the mechanical stirring preparation technique of ZL702 Alloy Composites reinforced by Si C particulate. Reference hydraulic simulation study of the influence of particle density and fluid nature on the particle movement of the mixing process. We have developed prepared technique of ZL702 Alloy Composites reinforced by Si C particulate by stirring casting. By metallographic observation and analysis of the mechanical properties of the composites, we study the impact on the material properties of stirring process parameters: mixing temperature, stirring speed, stirring time and Si C content. In the preparation process we compared two ways to mix and two kinds of pretreatment methods of Si C particles. Finally, we prepare composites of different Si C content with the optimum process and then study the combined effects of particle content on the composite material. Experimental results show that:(1) In the experiment mixing process, the particle motion is in the main laminar flow zone, The force of fluid that particles suffered is proportional to the viscosity of fluid, the particle settling velocity is inversely proportional to the fluid viscosity, is proportional to the density difference between the particles and the fluid.(2) In the experiment mixing process,we use graphite spiral rotor and when the stirring speed is100r/min, stirring time is 10 min, stirring temperature is 710℃, the overall performan-ce of sample is relatively good. In tensile strength and elongation is of 50% each to calculate the proportion, primary and secondary factors that affect the mechanical properties of the prepared composites is stirring speed> stirring time> Si C content> stirring temperature.(3)Electroless nickel plating process to improve wetting effect of the Si C particles and molten aluminum is obvious, aluminum surface is clean after Si C was added. But compared with the roasting oxidation pretreatment process, electroless nickel plating treatment of particles is inefficient, difficult for a large number of particles pretreatment, but also brings into other impurity elements. In the way of add Si C particles, the Si C particles is easy to break up when it is added with stirring. But the preparation process inhale serious, and some particles is difficult to wet, gather in the crucible wall. When the particles and alloy togather melt then stir, it can avoid the intake, and the wet between particles and liquid aluminum is good. But the particles tend to agglomerate, is difficult to disperse evenly, it need more time to stir.(4)We study the effects of different contents of Si C composite material on microstructure and properties, and found that with the increase of Si C content, the grain of the material gradually refined. When the particle content is 3%, the particle distribute well. At 4%, particle agglomeration occurs, the tensile strength of the material decrease after the first increase, it increases to maximum at 3% and then decreases significantly at 4%. Elongation increases after first decrease trend.Through studying the high temperature mechanical properties of materials.We find that the strength of the composites decrease as the temperature rises. High temperature strength of the particle reinforced composite material is superior to the base alloy, but as the temperature rises, this advantage is increasingly weak.