Study On Microstructure And Mechanical Properties Of SiC_p/Al 6082 Composites Prepared By Squeeze Casting

Aluminum alloy is one of the widely used metal materials,and it plays an important role in the fields of electronics,automobile industry,aerospace and so on.However,with the development of human science and technology,a single aluminum alloy is often difficult to meet people's requirements for comprehensive properties of materials.Aluminum matrix composites have gradually become a research hotspot and focus because of their low density,high specific strength and specific modulus,good dimensional stability,and more choices of matrix alloys.Due to the simple production process,low cost,and material isotropy of particle-reinforced aluminum matrix composites,the properties of composites can be adjusted by changing the size,volume fraction and heat treatment process of the reinforced particles,and have been developed rapidly.Among them,SiC particle-reinforced aluminum matrix composites are the most widely used particle-reinforced composites.At present,there are few researches on the use of squeeze casting methods for composite materials with 6082 aluminum alloy as the matrix.This paper combines mechanical stirring,permanent mold casting and squeeze casting to prepare micron SiC_p/Al6082 composites,nano SiC_p/Al 6082 composites and hybrid micro/nano SiC_p reinforced aluminum matrix composites.Mainly study the influence of SiC content and squeeze casting on the microstructure and mechanical properties of SiC_p/Al 6082 composites,and analyze the strengthening mechanism.On the basis of the above,exploratory experiments were carried out by mixing micro SiC_p and nano SiC_p to explore the influence of hybrid micro-nano SiC_p on the microstructure and mechanical properties of composite materials.Micron SiC_p/Al 6082 composites were prepared by permanent mold casting and squeeze casting.Micron SiC_p was successfully added to 6082 aluminum alloy by mechanical stirring method.The addition of micron SiC_p helped to refine the grain size of6082 aluminum alloy.As the content of micron SiC_p increases,the average grain size of the composite material is significantly reduced.However,the addition of SiC_p increases the porosity of 6082 aluminum alloy to a certain extent,and the porosity increases with the increase of SiC_p content,and the porosity of the composite material decreases under extrusion conditions.The micron SiC_p/Al 6082 composite with 2 wt.%SiC_p content prepared by squeeze casting has better comprehensive properties.The tensile strength,yield strength,elongation and hardness of the composite are increased by 10.73%,72.7%,193.9%and 25.2%,respectively,compared with the 6082 matrix alloy.The nano SiC_p were added to the matrix alloy by mechanical stirring,nano SiC_p/Al6082 composites were prepared by squeeze casting process.The nano SiC_p/Al 6082composites with fine grains were obtained by squeeze casting,and the average grain size decreased with the increase of the content of SiC_p.Like micron SiC_p,the addition of nano-SiC_palso increases the porosity of the matrix alloy,and correspondingly,the porosity of the composite material decreases under extrusion conditions.The tensile strength,yield strength,elongation and hardness of nano SiC_p/Al 6082 composite prepared by squeeze casting are increased by 13.67%,74.31%,212.59%and 35.10%compared with the 6082 base alloy,respectively.The hybrid reinforced aluminum matrix composites with micro/nano SiC_p were prepared by permanent mold casting.Mixture of micron and nano SiC_p has a certain refining effect on the grain structure of the composites,but the effect is not obvious compared with that of adding micron or nano SiC_p alone.Comparing with the 6082 matrix alloy,the yield strength,elongation and hardness of the hybrid micro-nano SiC_p reinforced aluminum matrix composites are increased by 50.97%,14.18%and 21.14%.