Effect Of Basalt Particles(Scale) On Microstructure And Properties Of Aluminum Matrix Composites

Because of low density,high specific strength and high specific modulus,aluminum matrix composite is one of the most studied and applied composites in metal matrix composites.Aluminum matrix composites reinforced by particles that are widely studied have many problems such as poor wettability between particles and matrix,density differences,poor interfacial bonding.It caused uneven distribution,high manufacturing cost and many problems in particles reinforced aluminum matrix composite now.In order to effectively solve the problems of aluminum matrix composites,this thesis selects amorphous basalt as a new type of reinforcement to fabricate aluminum matrix composites.The powder mixing process,sintering process,microstructure and properties of amorphous basalt reinforced aluminum matrix composites were studied in this work.In this thesis,7075 aluminum alloy and amorphous basalt powder are mixed by mechanical ball milling,and the uniformity of mixed powder is quantitatively analyzed.Powder metallurgy method is used to prepare the amorphous basalt particle reinforced aluminum matrix composite.The optimized preparation process of aluminum matrix composites with different component is obtained based on the experimental study.Aluminum matrix composites and 7075 aluminum alloy composite with different mass percents of basalt reinforcement are propagated in this process.Microstructure characterization and performance test of the composites were carried out.The results show that with the increase of the basalt particles,whether the matrix is pure aluminum or 7075 aluminum alloy,there is a critical value optimized.When the mass percent of basalt is 9wt.%,the optimized mechanical properties are determined as following:the density of aluminum matrix composite material is 2.605g/cm3,hardness is 62HV,elastic modulus is 71.2GPa,tensile strength is 203MPa,elongation rate is 1.8%.While when the mass percent of basalt in 7075 aluminum alloy matrix composite material is 4%,the density is 2.834g/cm3,hardness is 155HV,elastic modulus is 72.7GPa,tensile strength is 572MPa.The fracture morphology observation shows that with the increase of the content of the basalt particles,the brittle tendency of the aluminum matrix composites is more serious.In addition,the basalt scales reinforced aluminum matrix composites is prepared for analyzing the microstructure of the matrix interface.Result shows that the interface is excellent,and there is a reaction layer between basalt and aluminum matrix.It means that the interface is metallurgical bonding.