Study Of Preparation And Properties Of Graphene And Graphene-reinforced Al-20Si Composites

This paper is based on the actual application of electronic packaging materials.Graphene aluminum matrix composite, including grapheme and Al-20Si, was madeby the ball milling and pressure infiltration process. The raw graphene prepared andgraphene reinforced aluminum matrix composite was analyzed and characterized byscanning electron microscopy, XRD, transmission electron microscopy, atomicforce microscopy, infrared spectroscopy, Raman spectroscopy and other detectionmethods. The electronic tensile testing machine, thermal expansion analyzer,thermal conductivity tester, friction and wear tester and other equipment were usedto test the performance of grapheme/Al-20Si composites.With high heat conducting graphite as raw materials, expanded graphite can beprepared to synthesis graphene materials by the improved Hummers method.Prepared without ultrasonic, or short ultrasound, the layers can be peeled. Thelayer of Graphene was thin, just within1~10; the thickness of graphene preparedwas between0.34~3nm; the grapheme prepared without other oxygen containingfunctional groups also had a high degree of graphitization.Compared with Al-20Si alloy, the properties of the composite were greatlyenhanced and improved. The elastic modulus of the composite increased withincreasing of graphene, which was approximately linearly, matching the mixing rule.The bending strength and tensile strength increased firstly and then decreased withthe increasing of graphene content, such as when graphite content was3vol.%, thebending strength and tensile strength reached the highest, respectively617MPa and363MPa. Compared to the matrix Al-20Si, the reason why the strength andplasticity increased was different. The ductility of Al-20Si improved, mainlybecause of that the graphene, with huge specific surface area and surface folds, candeform while composite material deforms. The dispersion of graphene, known asnano-size, showed a dispersion strengthening effect, which impeded the motion ofdislocations. Meanwhile the graphene could play the role as bear loads in compositematerials.The ability, resistance to high temperature compression, improve with theaddition of graphene. The coefficient of thermal expansion decreased significantlyby inhibiting the expansion of matrix. The coefficient of friction and wear of graphene composites decreased significantly with increasing graphene content,when the content reached to7vol.%, the coefficient of friction and wear reduced to~0.165, which was stable. It showed that the grapheme/Al-20Si composite materialscould be a hind of good self lubrication materials.