| The paper studied the mechanical stirring process to prepare ZL104/ZL109 alloy composites and eutectic aluminum matrix composites reinforced by SiC particles, studied the preparation techniques of ZL104/ZL109 alloy composites and eutectic aluminum matrix composites are 3.6Kg respectively. The percentage of the SiC particles was all 20% in accordance with the quality fraction of the matrix alloys and the average diameter of SiC particles is 15μm, 30μm,and 50μm.And the volume fraction is 17.2%. And(1)ZL104 alloy as the matrix alloy, and the mass ration of three kinds of particles with diameters of 15μm, 30μm and 50μm is one-third(the volume fraction of various particle sizes is respectively 5.733%),called craft One; and(2)ZL109 alloy as the matrix alloy, the volume fraction of 15μm, 30μm and 50μm is respectively 4.3%,7.224%,5.676% called craft Two; and(3)the eutectic aluminum silicon alloy adding the SiC particles with diameters of 15μm, 30μm accounts for 10% respectively, The good fluid composite slurry of reinforced is obtained, and studied under four different casting conditions the forming processes of the eutectic aluminum silicon alloy, called craft A,B,C,D and the fine performance compound materials pistons of ZL104/ZL109 alloy with completely bright and clean, the organization to be compact are obtained, and the SiC particles are gathered in the forehead of the pistons.Based on experiment data, the paper simulated the distribution and the volume fraction size of the aluminum liquid and SiC particles of thick-walled and thin-walled pistons with SiC particles added in the pistons, and the software used to simulate is at present popular commercial software, FLUENT software. And the experimental results were compared with the results of the simulation. The experiment results showed that, SiC particle size is bigger, it is more easily to gather to the piston crown far-end, forms has certain thickness particle layer, Three kind of particle size SiC added in the pistons the SiC particles volume fraction compares two improving, the SiC particles volume fraction of the thin-walled piston is higher than that of the thick-walled piston. The comparison result shows that the simulation results are in approximate agreement with the actual results ,and the numerical calculation method of particle distribution under a centrifugal force is basically correct. The performance of the pistons obtained by ZL104(craft one) surpasses the one obtained by ZL109(craft two),and the microstructure and performance of test specimen D (craft D) is the best one ,surpasses other pistons obtained by other crafts of the eutectic alloy.The heat treatment processing of the pistons formed by centrifugal casting have also been studied, carried on the solution and the ageing treatment of metal to the pistons; Macrostructure and microstructure of composite piston have been also discussed, hardness and wear resistance of the pistons before and after heat treatment measured; The influence of heat treatment on the properties of pistons was also analysised. Results showed that: heat treatment enhanced hardness of composites and it was a way to increase hardness of metal matrix composites reinforced by particles; while the degree of hardness enhancement in particle-rich region was smaller than that in particle-free region; ageing heat treatment reduced the wear resistance of composites materials parts reinforced by particles.Finally, a piston was machined with the gloss in the ring groove of the piston which was from the ZL104 alloy as the matrix alloy by centrifugal casting. |
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