Study On Microstructure And Property Of SiC_p And Gr Particle Reinforced Aluminum Matrix Composites Prepared By Semi-solid Pouring

SiCp/Gr/ZL101 aluminum matrix composites were prepared by combining semi-solid stirring and gravity pouring method of normal temperature and low superheat. The temperature of the two preparation methods is respectively 730℃and 630℃.And the effects of SiCp and Gr with different volume fractions on the microstructure and property of aluminum-based composites were studied. The result shows that the reinforced particle is dispersive and well combined with the matrix alloy by the two preparation methods.For the purpose of solving the problems of Wettability between reinforced particle and matrix alloy and its uniformity of distribution in composites,SiC particles were pretreated at 1000℃before stirring. During the process of manufacturing,when matrix alloy has melted and fusion is cooling down to 600℃, putting SiC and Gr particle which are preheated to 300℃into the fusion. In the meantime mixing the fusion and reinforced particles by the whirlpool which is made by the running stirrer. Stirring rate is 1400rad/min and the duration is 15 minutes. With the increase of temperature of fusion,the stirring rate decrease gradually until the pouring temperature. The microstructure and property of SiCp/Gr/ZL101 composites were investigated by microstructure observation, mechanical property test, fracture scanning, damping measurement and wear resistance measurement.The results of microstructure observation show that the primary phase of ZL101 alloy is dentrite structureα-Al when the pouring temperature is 730℃While the dentrite structure a-Al transforms into rosaceous morphology and the crystals are significantly refined when the pouring temperature is 630℃SiCp and Gr distribute uniformly in composites without segregation phenomena fundamentally.Tensile test shows that the tensile strength of SiCp/Gr/ZL101 composites is higher than that of ZL101 matrix alloy and it firstly increases, then decreases along with the rising volume fractions of SiCp while the elongation gradually decreases.Especially, the tensile strength of the composites is 191MPa,which increase by 32% compared to that of ZL101 alloy. The mechanical property of composite prepared by method one is better than that of composite prepared by method two when the volume fractions of reinforced particles is same.The fracture analysis shows that the plasticity of SiCp/Gr/ZL101 composites is reduced with the increase of the volume fraction of SiCp. The fracture mechanics of SiCp/Gr/ZL101 composites are dimple fracture →quasi-cleavage fracture→cleavage fracture→intergranular fracture.The results of damping measurement show that the internal dissipation Q-1 of SiCp/Gr/ZL101 composites is higher than that of matrix alloy and gradually increases along with the rising SiCp volume fractions.The damping mechanism of the composites is mainly the combined effects of both dislocation damping and interfacial damping. The damping property of composite prepared by method one is better than that of composite prepared by method two when the volume fractions of reinforced particles is same.The results of wear resistance measurement show that the abrasion loss of SiCp/Gr/ZL101 composites is lower than that of matrix alloy and gradually decrease along with the rising SiCp volume fractions. The abrasion resistance of composite prepared by method one is better than that of composite prepared by method two when the volume fractions of reinforced particles is same. With the increase of SiCp volume fractions, The wear mechanics of SiCp/Gr/ZL101 composites transform from adhesive wear and abrasive wear into abrasive wear...