Studay On The Influence Of Different Content Graphene Nanoplatelets On The Properties Of AZ31B Magnesium Alloy

Graphene nanoplatelets(GNPs)are the promising reinforcement material,but due to its large surface area and poor wettability,the preparation of GNPs-metal composites is still a challenging task.Therefore,it is of great practical significance to develop a preparation method that can improve the wettability between GNPs and the magnesium matrix.In this paper,AZ31 B alloy and GNPs-magnesium chips mixture is used for the "Sandwich" stacking method to prepare AZ31 B magnesium alloy composites with0.1wt.%,0.3wt.%,0.5wt.%,and 0.7wt.% GNPs.The composite materials were analyzed with optical microscope,scanning electron microscope and transmission electron microscope.The grains of AZ31B-0.5GNPs composite material have been well refined,and GNPs can be uniformly and stably distributed on the matrix.The mechanical properties at room temperature show that when 0.5wt.% GNPs are added,the microhardness,yield strength,ultimate tensile strength,and fracture strain of the composite material increase by 25.8%,44.1%,63.5%,and 27.5%,respectively as compared to the matrix alloy.Through first-principles calculations,an interface model in which Armchair and Zigzag hand-shaped GNPs are embedded vertically on the surface of Mg(100)and an interface model in which GNPs are embedded horizontally on the surface of Mg(111)have been established.The analysis of the electronic structure shows that GNPs vertically embedded in the surface of Mg(100)C atoms and the first proximal magnesium atoms have high bonding strength and can form covalent bonds,indicating that GNPs can be used as an excellent reinforcing phase for magnesium and alloys.But for GNPs embedded horizontally on the surface of Mg(111),the binding mechanism of the interface is physical adsorption.In addition,the interface model of GNPs/Mg(111)doped with different Al atom concentration is also established.The calculation results show that the addition of Al atoms is beneficial to the stability of the interface,and as the concentration of Al atoms increases,the interface becomes more stable.