Effect Of Secondary Phases On The Electromagnetic Shielding Effectiveness Of Magnesium Alloy

Given the rapid development of electronic science and technology,electromagnetic radiation pollution has become the fifth most prevalent pollution after air,water,noise,and solid-waste pollution.Therefore,electromagnetic interference has become a matter of concern,especially in the field of 3C and electrical apparatus.Research on the development of electromagnetic shielding materials has rapidly expanded,and most related studies have focused on the application of metallic materials,thin films,conductive polymers,and composite materials as electromagnetic shielding materials.The research on magnesium alloy as electromagnetic shielding material has been carried out,and it is necessary to further study the electromagnetic shielding mechanism of magnesium alloy.Therefore,the influence rule and mechanism of the second phase orientation in magnesium alloy on the electromagnetic shielding performance of magnesium alloy are studied systematically will expand the application of magnesium alloys in the field of electromagnetic compatibility.On the basis of Mg-Zn and Mg-Sn alloys,the relationship between the second phase orientation and the electromagnetic shielding properties of the alloy was studied by rolling treatment with different deformation amount and subsequent solid solution aging treatment.Based on the conclusions obtained,Mg-3Sn-xZn-0.2Ca-0.3Ce alloy was designed by optimizing the composition of the alloy.The electromagnetic shielding and mechanical properties of the alloy were studied by rolling and subsequent solution aging treatment.Several results can be concluded as follows:?1?After rolling and subsequent solution treatment,the Mg-Zn alloy obtained a rod-shaped?₁'phase that precipitated along the cylinder plane,and the Mg-Sn alloy obtained a disk-shaped Mg₂Sn phase precipitated on the basal plane.After aging treatment,the SE value increased gradually with the aging time.With the increase of rolling reduction,the increase of SE value of Mg-Zn alloy is gradually reduced,and the decrease of Mg-5Zn alloy is greater than that of Mg-3Zn alloy.The increase in the SE value of the Mg-Sn alloy gradually decreased,and the Mg-5Sn alloy decreased more than the Mg-3Sn alloy.?2?Compared with rod-shaped MgZn₂ phase,the plate-like Mg₂Sn phase precipitated along the?0001?plane can more effectively shield the propagation of the incident electromagnetic wave,and the secondary phase precipitated in the plane perpendicular to the incident direction of the electromagnetic wave?basal plane here?,is more efficient to loss electromagnetic wave than the other,so that the electromagnetic shielding performance of the alloy can be improved.?3?Based on the Mg-Zn-Sn alloy,the alloy composition was optimized and the Ca and Ce were added to promote grain refinement and improve the precipitation phase to comprehensively improve the electromagnetic shielding and mechanical properties of the alloy.In the Mg-3Sn-xZn-0.2Ca-0.3Ce alloy,a hard,brittle and high temperature stable Mg-Sn-Ca-Ce quaternary phase was formed.The maximum texture strength of the alloy gradually increases as the Zn content increases.After aging treatment,the SE value of the alloy was higher overall,and the SE value gradually increased with the aging time.At 1000 MHz,the peak shielding effectiveness of the peak-aged Mg-3Sn-2Zn-0.2Ca-0.3Ce alloy is 88.4 dB.By precipitation strengthening,the comprehensive mechanical properties of the three alloys reach the best at the peak aging stage,and the Mg-3Sn-2Zn-0.2Ca-0.3Ce alloy has the best comprehensive mechanical properties:tensile strength of 355 MPa,yield strength of 222 MPa,and elongation of9.9%.In this paper,the Mg-Sn-Zn-Ca-Ce alloy sheet has excellent mechanical properties and the electromagnetic shielding performance is higher than the commercial standard requirements,so it has a good prospect of industrial application.