The Study On High Thermal Conductivity Magnesium Alloy And Its Heat Dissipation

With the high density and high power of electronic components in the fields of LED lighting,5G communication and new energy vehicles,the lightweight heat dissipation structure and the demand of its alloy materials with excellent heat dissipation and mechanical properties are rapidly expanding.High thermal conductivity magnesium Alloy profiles will have development opportunities.Now there is no corresponding standards in China and abroad and the technical specifications referenced by various manufacturers are not uniform,which restricts the status quo of the expanded application of high thermal conductivity magnesium profiles.In order to solve that mentioned problems,the National nonferrous metals Standardization Technical Committees lunches the drawing projects,called“High thermal conductivity magnesium Alloy profiles”.Leading by Chongqing University to compile and determine the suitable alloy varieties and recommended performance indicators at current stage.At the same time,in view of the fact that the magnesium alloy heat dissipation structure has better heat dissipation performance than the aluminum alloy structure of the same shape,the design experiment method has conducted a large number of data comparison tests.Combined with theoretical analysis to determine that the mechanism of magnesium alloy surface has good heat dissipation.The main conclusions drawn are as follows:(1)Compiled national standard GB/T 38714-2020"High Thermal Conductivity Magnesium Alloy Profiles",through the research of related study and market application on high thermal conductivity magnesium alloys and the trial production test with the composition,mechanical properties and thermal conductivity.Determined that the alloys suitable for inclusion are M1C,M2S,ZE20M,ME20M,ZK60A,ZM51M,and the thermal conductivity threshold value of the high thermal conductivity profile is110MPa.(2)A cylindrical boiling water method was established to compare the heat dissipation capabilities of different alloys,and the surface heat exchange capabilities of different alloys and surface treatment methods could be evaluated.The experiment found that the heat dissipation performance of pure magnesium is better than that of pure aluminum at 50??90?,and it is closer to the heat dissipation performance of pure aluminum at 40??50?,and less than that of pure aluminum at 30??50?.(3)The reason why the pure magnesium structure with the same shape has better heat dissipation performance than the pure aluminum structure at higher temperatures can be attributed to the blackness of the pure magnesium surface is 0.95,which is much higher than the blackness of the pure aluminum surface 0.03.At higher temperatures,the radiant heat dissipation capacity of the surface is dominated by blackness.As the temperature of the heat source in the cylinder decreases,the advantage of the radiant heat transfer on the magnesium surface decreases.The thermal conductivity rate(237W·m^-1·K^-1)of pure aluminum is higher than that of pure magnesium(158 W·m^-1·K^-1),and the overall heat dissipation capacity of the pure aluminum structure gradually dominates.(4)After spraying the same protective layer on the surface of the magnesium cylinder and the aluminum cylinder,the original blackness advantage of the magnesium alloy surface disappears.Then it becomes a combined effect of the overall thermal resistance and the blackness of the coating surface.When the surface heat exchange conditions are similar,the heat dissipation capacity of the cylinder is positively related to the thermal conductivity of the alloy.The low overall thermal resistance of the heat dissipation and the high blackness of the anti-corrosion paint surface is conducive to improving the heat dissipation performance of the overall components.(5)Combined with the compilation and data verification work of the national standard"High Thermal Conductivity Magnesium Alloy Profiles"and confirmation research on the advantages of magnesium heat dissipation structure,it can indicate the future development direction of the lightweight and low-cost design of metal heat dissipation structure.The overall thermal conductivity and natural surface emissivity of the heat dissipation structure substrate determined by the coordinated design of the alloy type and composition and the heat resistance and heat exchange coefficient of the anti-corrosion layer when the radiator needs need to be considered as a whole.