Microstructure And Mechanical Properties Of High Entropy Alloy Composite A356 Aluminum Matrix Material

Aluminum matrix composites have the advantages of light weight,high specific strength and wear resistance,which have broad application background in aerospace,automobile and other fields.Ceramic particles and metal particle fibers are commonly used as reinforcement materials.These composites often have good strength and toughness,but there are still many problems,such as the poor interface between the particle reinforcement and the matrix metal,and the uneven distribution of particles in the composites.High entropy alloy is a new type of multi principal component alloy,which has many properties different from traditional alloys,such as good thermal stability and high resistance.High entropy alloy and aluminum melt matrix have natural interface bonding characteristics between metals.Using high entropy alloy particles instead of traditional ceramic particles to strengthen aluminum matrix composites is conducive to solve the problem of poor wettability between ceramic particle reinforcement and metal matrix.In this paper,Al_0.25Cu_0.75FeNiCoCr particle reinforced A356 aluminum matrix composite was studied.The influence of mechanical alloying time on the morphology and crystal structure of high entropy alloy was studied by XRD,laser particle size analyzer and SEM.The preparation technology of high entropy alloy particles was determined.The high entropy alloy particles were prepared by squeeze casting under the common stirring and gas dispersion stirring processes The effects of different processes on the morphology and microstructure,particle dispersion and agglomeration and mechanical properties of aluminum matrix composites were analyzed by means of metallography,SEM,EDS,tensile properties and hardness.The microstructure and mechanical properties of high entropy alloy and Si C particle reinforced aluminum matrix composite under different mass fraction were compared,and the relevant strengthening mechanism was analyzed and discussed.The results show that:with the increase of mechanical alloying time,the particle size of metal powder increases at first and then decreases,and then gradually forms high entropy alloy powder with simple cubic structure;the aluminum matrix composite prepared by gas dispersion adding high entropy alloy particles can significantly reduce the agglomeration phenomenon,improve the morphology and distribution of reinforcement phase in aluminum matrix,so as to improve the morphology and distribution of reinforcement phase in aluminum matrix With the increase of the mass fraction of high entropy alloy particles,the grain size of the aluminum matrix composite decreases obviously,and the grain refinement degree increases;the hardness and tensile strength of the high entropy alloy aluminum matrix composite first increase and then decrease with the increase of the mass fraction;when the addition amount is 5%,the high entropy aluminum alloy aluminum matrix composite material has good mechanical properties The results show that the hardness and tensile strength of the composites are 91.7HV and 268MPa,and the elongation is 6.5%,which is 26.7%and 19.1%higher than that of the ordinary A356 aluminum alloy matrix.The fracture morphology shows that the fracture is a mixed fracture of ductile tearing and brittle fracture,which further increases the high entropy alloy particles and agglomerates;for Si C particle reinforced aluminum matrix composites,the high entropy and high entropy alloy particles are mixed The results show that the hardness and tensile strength of aluminum matrix composites are similar with the increase of additive content;the maximum tensile strength of aluminum matrix composites is basically the same,but the hardness of high entropy alloy reinforced aluminum matrix composite is significantly higher than 77.5HV of Si C particle reinforced aluminum matrix composite,which is increased by 18.2%.