Microstructure And Mechanical Properties Of ALNnp/6061Al Composite Prepared By Flake Ball Milling + Pressure Infiltration

The nano-AlN particles have the advantages of not interfacial reaction with Al as a derivative compound of Al,and thus can be used as a potential reinforcement.In this paper,nano-AlN particles were selected as reinforcements,and 6061Al was used as the matrix.AlNnp/6061Al composites were prepared by pressure infiltration technique by flaking ball-milled Al powders to disperse nano-AlN particles.Microstructure analysis was carried out by means of scanning electron microscopy,transmission electron microscopy,laser confocal microscopy,etc.The mechanical properties of the composites were tested by an electronic tensile tester to discuss the influencing factors of the mechanical properties of the composites.The nano AlN particles were subjected to dispersion treatment by flaking ball milling 6061 Al powder.After adding 10wt.%n-butanol as a process control agent,the particle diameter distribution of the ball milled mixed powder ranges from 8 to 12?m,and the particle diameter distribution of the 10 wt.%stearic acid powder is between 4and 8?m.When the n-butanol content is 7.5 wt.%,the powder diameter distribution is between 3-8?m,and 10 wt.%n-butanol is added as the process control agent.The 6061Al powder maintains a good flaky morphology after ball milling;Ball milling at 350rpm for 6 hours 5wt.%AlNnp/6061Al mixed powder with a diameter of 8-12?m,ball milling at 400 rpm for 6 hours,powder diameter distribution between 2-8?m,ball milling at 350 rpm After the hour,the powder diameter is between 2-10?m,and the6061Al powder maintains a good flaky morphology after 6 hours of ball milling at 350rpm;when the content of the added nano-AlN particles is 10 wt.%and 15 wt.%,respectively,the powder The body diameters are respectively distributed between 2-8?m and 1-5?m.Therefore,10 wt.%n-butanol was added and ball milled at 350 rpm for6 hours.The 5 wt.%AlNnp/6061 Al mixed powder was an optimized ball mill dispersion process.The microstructure of AlNnp/6061Al composite is uniform.After electrolytic corrosion,the flaky 6061Al is corroded in the composite,showing an island-like black area,while the infiltrated 6061Al liquid shows a continuous gray-white area.After the energy spectrum analysis,the nano-AlN is obtained.The particles are distributed on the surface of the sheet 6061Al.After the composite material is extruded,the grain of the6061 Al matrix is remarkably refined,and the reinforcement distribution is improved.The grain size of the matrix is reduced from 2-20?m to 1-3?m,and the grain orientation has a preferred orientation in the<111>direction.After the extrusion,the material is subjected to electrolytic corrosion test,and the flaky 6061Al is observed under the scanning electron microscope.After corrosion,it is semi-continuous and the size is between 1-3?m.XRD analysis shows that the composite consists mainly of Al and AlN,and contains a small amount of Al₂O₃.Under the transmission electron microscope,the interface between Al and AlN is well formed,smooth and flat,no Interface reaction product.The addition of 10wt.%n-butanol increased the average tensile strength of the composite after adding 10wt.%stearic acid as the process control agent ball mill powder by 25%?from 310MPa to 387MPa?;adding 10wt.%n-butanol ratio The average tensile strength of composites with 7.5 wt.%n-butanol increased by 8.5%?from 410 MPa to445 MPa?;at 350 rpm,the ball-milled powder has a higher tensile strength than the ball-milled powder at 400 rpm.33%?from 334MPa to 445MPa?;the average tensile strength of the composite prepared by ball milling mixed powder for 6 hours after ball milling for 8 hours is 22%higher?from 366MPa to 445MPa?;3wt.%,6wt.The average tensile strengths of%,9wt.%AlNnp/6061Al composites are 445 MPa,368 MPa and 330MPa,respectively.With the increase of AlN content,the tensile strength shows a downward trend.After hot extrusion treatment,the average of composite materials The yield strength is increased by 85%?from 180MPa to 334MPa?,the average tensile strength is increased by 15%?from 387MPa to 445MPa?;the tensile strength of the tensile specimen after extrusion aging treatment is up to 473MPa,after annealing,extrusion Sample tensile strength of up to 403MPa.