Al₂O₃ Particle Reinforced 7075 Aluminum Matrix Composites Study On Preparation Technology

In this paper,Al₂O₃particulate reinforced aluminium matrix composites were prepared by stirring casting method.The matrix alloy is 7075 aluminium alloy.By adding Al₂O₃and aluminium powder into 7075 aluminium alloy melt,the wettability of reinforcement particles and aluminium alloy matrix can be increased,and the problem that Al₂O₃particles can not easily be added into aluminium melt because of its low density can be solved.Finally,as far as possible,the Al₂O₃particles can be dispersed in the matrix and the agglomeration of reinforcement particles can be avoided.In order to obtain the preparation technology for improving the microstructures and mechanical properties of particulate reinforced aluminium matrix composites,an orthogonal experiment of L₉?3⁴?was designed.Al₂O₃content,particle size composition and stirring time were selected,and three levels were set for each factor.The importance of the factors affecting the experimental results was analyzed and the optimum technological parameters for preparing Al₂O₃particulate reinforced aluminium matrix composites were obtained.?1?After ball milling,the agglomeration of nano-Al₂O₃particles can be improved and evenly dispersed on the surface of aluminium powder.After ball milling,the aluminium powder can be refined,and eventually the powder with uniform mixture of Al₂O₃particles and aluminium powder can be obtained.After XRD analysis,the nano-Al₂O₃particles after ball milling and grinding can be well combined with aluminium powder.?2?In mechanical properties,the tensile strength and hardness are mainly analyzed,and the two indexes are analyzed intuitively,variance and trend.The main factor affecting the hardness of the composites is the particle size of Al₂O₃,followed by the stirring time?min?,and the main factor affecting the tensile strength of the composites is the C stirring time?min?.?3?The optimum technological parameters of the composite structure should be as follows:the content of Al₂O₃is 1.5%,the composition of Al₂O₃particles is single nano-scale,and the stirring time is 20 minutes.Al₂O₃reinforced composites were prepared by mechanical stirring,and the reinforced phase particles Al₂O₃were effectively added to 7075 matrix.?4?The best way to improve the structure and properties of the composites is that the content of Al₂O₃is 1.5%,the composition of Al₂O₃particles is single nanometer,and the stirring time is 20 minutes.Under this process parameters,the mechanical properties and structure are in the best state.The hardness and tensile strength of the sample are 124HB and 218 MPa,which are greatly improved compared with the hardness?110HB?and tensile strength?154 MPa?of 7075 alloy with as-cast structure.The hardness increased by 12.7%and the tensile strength increased by 41.5%.