Effects Of Reciprocating Extrusion Process On Microstructure And Properties Of CNTs/Mg-Li Composites

With the rapid development of the aerospace and 3C industries,the demand for lightweight structural materials is becoming increasingly pressing.The existing lightweight structural materials have gradually failed to meet the development needs of related fields.Magnesium-lithium alloy,as the lightest structural material at present,has broad prospects in light-weight applications,but the shortcomings of low strength and low modulus of magnesium-lithium alloy severely limit its application in related fields.In this paper,CNTs/Mg-Li composites were prepared by improved foil metallurgy,the microstructure and properties of the composites were studied,and the reciprocating extrusion process of matrix alloy LA103 Z was simulated by DEFROM-3D.CNTs pickling can introduce hydroxyl,carboxyl and other functional groups on the surface of CNTs to improve dispersion of CNTs;in the spray deposition process,the concentration of 0.5g/L CNTs dispersion can achieve good uniform deposition of CNTs.CNTs are stacked in layers Form deposited on the LA103 Z alloy foil.The strength and elastic modulus of CNTs/Mg-Li composites prepared by the method described in this article have been improved.The content of carbon nanotubes is 1wt.%,2wt.%,4wt.%.The tensile strength of the composite materials is increased to 270 MPa,289MPa,and 273 MPa,respectively.Compared with the 219 MPa of the LA103 Z matrix alloy,they are greatly improved.The elastic modulus of the composites with carbon nanotube content of 1wt.% and 2wt.% were increased to 49 GPa and 51 GPa respectively;continue to increase the content of CNTs,the elastic modulus will not change.However,the elongation of the composite material has been seriously reduced compared to the LA103 Z matrix alloy,from 18.2% of the LA103 Z matrix alloy to less than 5%,and the elongation of the composite material is 4.9% and 3.4%,respectively.,2.3%.The main reasons for strengthening CNTs/Mg-Li composite materials are grain refinement,dislocation strengthening and the addition of carbon nanotubes.In the CNTs/Mg-Li composite,the carbon nanotubes react with the LA103 Z matrix alloy to form Li2C2,which leads to a sharp drop in the elongation of the CNTs/Mg-Li composite.In addition,(Mg,Li,Zn)phases are simultaneously formed in the composite material.DEFROM-3D simulates the reciprocating extrusion process of LA103 Z matrix alloy,inferring that reciprocating extrusion can promote the "re-dispersion" of CNTs in CNTs/Mg-Li composites.The existence of the layered structure can also promote the "redispersion" of CNTs,but the redistribution mechanism of the two is different;the layered structure LA103 Z matrix alloy relies on interlayer stress,and the LA103 Z matrix alloy relies on a wide range of materials.