With the advent of the 5G communication era, the integration of electronic communication equipment and products is gradually improving, and the calorific value per unit volume is also increasing. U ovo vrijeme, relevant materials and structures are required to have good thermal conductivity to ensure normal equipment and products. work and prolong life.
Taking the 5G communication filter as an example, it has high power and high integration. In order to improve the heat dissipation capacity, the filter housing structure is usually designed with many irregular thin-walled heat sinks. For the mass forming and manufacturing of such structural shells, the die-casting process has significant efficiency and cost advantages. The density of metal aluminum is only 1/3 of that of steel and iron, and it has a huge potential for lightweighting. In recent years, it has been widely used in automobiles, communications, aerospace and other fields.
The room temperature thermal conductivity of pure aluminum is about 237 W/(m·K), and the thermal conductivity is excellent. However, the strength of pure aluminum is low, and some alloying elements are often added in actual production to improve its mechanical properties, and the addition of alloying elements will have a certain impact on its thermal conductivity. Obično, alloying elements strengthen aluminum alloys in the form of solid solution atoms, formation of intermediate phases or precipitation strengthening, but whether they exist in the form of solid solution atoms or intermediate phases, they will bring a large number of vacancies, dislocations and other crystals to the alloy. The existence of these defects increases the probability of free electron scattering in the alloy, and the number of electrons for effective heat conduction decreases, resulting in a decrease in the thermal conductivity of the alloy.
In order to take into account the mechanical and thermal conductivity of aluminum alloys, researchers have conducted in-depth research. Wen Cheng studied the influence of 22 alloying elements on the electrical and thermal conductivity of industrial pure aluminum, and found that the influence of different elements is different. The addition of transition elements such as Mn and Cr will rapidly decrease the electrical and thermal conductivity of pure Al. The influence of Zn, Sr and rare earth metamorphic elements is small. Li Linjun found that different magnesium-silicon ratios have different effects on the thermal conductivity of aluminum alloy 6063. When the magnesium-silicon ratio is 1.5, the thermal conductivity of the alloy is the best.
Lumley et al. studied the effect of alloy composition and heat treatment on the thermal conductivity of Al-Si-Cu series aluminum alloy die castings. The study showed that the thermal conductivity of some alloys can be increased by more than 60% by using heat treatment. Kim et al. tested the thermal diffusivity of Al-1Si and Al-9Si alloys under different heat treatment conditions, studied the relationship between thermal diffusivity and the solid solution and precipitation of silicon phase, and concluded that the dissolved silicon in the solution treated samples re-precipitated It will increase the thermal diffusivity of the alloy.
Choi et al. studied the influence of mold temperature on the thermal and mechanical properties of aluminum alloys, and found that the higher the mold temperature, the slower the alloy solidification rate. U ovo vrijeme, the larger the silicon particles, the better the thermal properties of the alloy. After aging treatment, different molds The mechanical strength of the alloys becomes similar at temperature.