Precipitation Behavior And Mechanical Properties Of 6013 Al Alloy Based Composites Reinforced By SiC Particles

6013 aluminum（Al-Mg-Si-Cu）is a kind of heat-treatable reinforced aluminum alloy with excellent comprehensive properties and wide application prospects.Compared with other 6 series aluminum alloys,it has higher strength,but also can maintain good corrosion resistance,fracture toughness,fatigue resistance and weldability.In order to adapt to the modern industrial production comprehensive performance is more and more stringent requirements for the materials,particle reinforced aluminium matrix composites is regarded as a research direction of high performance,not only than high specific strength and modulus,but also better than base material of high temperature resistant performance and wear resistance,now as a lightweight structural material widely used in aerospace and vehicle engineering,It also has excellent application prospect in electronic devices.In order to obtain the lightweight materials with better comprehensive properties,SiC particles reinforced6013 aluminum matrix composites with dense and uniform structure and good particle dispersion were prepared by combining cold isostatic pressing,hot isostatic pressing and extrusion.The effect of different aging temperature and time on the aging precipitation behavior of 6013 aluminum alloy was analyzed,and the effect of deformation heat treatment process on the mechanical properties of 6013 aluminum matrix composites reinforced by SiC particles was studied,which provided some theoretical guidance for the industrial application of SiC.It is found that the strength and hardness of 6013 matrix can be significantly improved by SiC_preinforcement phase,but the plasticity of 6013 matrix decreases rapidly,and the fracture of 6013 matrix presents obvious brittle fracture characteristics.The precipitated phase of both aluminum alloy and composites is Mg₂Si,but the presence of SiC_pchanges the morphology of impurity phase（Fe Mn Si）Al₆to a certain extent.Resistivity and the test results,combined with in situ SiC particles reinforced phase on the one hand,can lead to resistivity rapidly rising of6013 aluminum alloy matrix,and on the other hand can play the role of accelerated precipitation phase precipitation,the introduction of SiC particles can significantly improve the matrix of the grain boundary area,in the process of heat treatment can provide a large number of heterogeneous nucleation,conducive to the strengthening phase precipitation and precipitation;Under the condition of solution treatment at540℃/2 h,the optimum artificial aging process of SiC_p/6013Al composite is150℃/8 h,and the peak aging hardness is 180 HV_0.2.,the yield strength is 388MPa,the tensile strength is 522 MPa,compared with 6013 aluminum alloy with the same chemical composition,the peak hardness is increased by 29.5%,the yield strength is increased by 19.6%,the tensile strength is increased by 48.7%.The deformation aging process can improve the yield strength,tensile strength and peak hardness of SiC_p/6013Al composites to a certain extent under the condition that the plasticity does not decrease,and the increase degree of the strength of the sample will increase with the increase of the reduction amount.When the deformation aging process parameters are 540℃/2h SS+R15%+150℃/8h AA,the optimal mechanical properties of the composites are obtained,and the peak hardness of the composites is 203HV_0.2,the yield strength is 480.0MPa,and the tensile strength is539.3MPa.Compared with the traditional heat treatment process,the elongation of the material is 4.47%.The composite samples treated by deformation-aging process have a high degree of dislocation density.The dislocation density in the composite is quantitatively calculated by XRD line broadening method.It is found that the dislocation strengthening stress provided by the dislocation density is the main strengthening mechanism of the composite.