In this paper, W-40wt% Cu is used as an example, and the mechanical ball milling composite powder-cold compaction-liquid phase sintering-hot extrusion and hot rolling processes can be used to prepare compact, fine-grained, and excellent performance composite materials. First, the W and Cu elemental powders are uniformly mixed by short-time, low-speed mechanical ball milling, and then cold-pressed and liquid-phase sintered. After sintering, through one hot extrusion and subsequent deformation cnc machining experiments on the W-40wt% Cu liquid-phase sintered billet, it was found that after one extrusion and two extrusions, the tungsten particles have obvious plastic deformation. ;
And after extruding and rolling the sample did not have this phenomenon. This paper also studies the changes in the conductivity and hardness of tungsten copper materials. The results show that after secondary extrusion, the hardness and electrical conductivity of tungsten copper materials are significantly improved; The conductive properties are reduced.
Application of tungsten copper material in electrical industry
The electrical contact is the "heart" of the entire electrical appliance, and the life of the electrical appliance is mainly determined by the wear of the electrical contact. Tungsten copper electrical contacts have been used on high-voltage switches for many years, especially on high-voltage high-current circuit breakers. In recent years, the main development directions of tungsten copper electrical contact materials are: research and development of tungsten copper and tungsten silver contacts for various new high-voltage and low-voltage switching appliances, such as large-sized tubular contacts of SF6 high-voltage circuit breakers and tungsten copper and Copper overall connection composite contacts, tungsten copper contacts for electric trains and new low-voltage electrical appliances Many countries in the world attach great importance to its research and development, and contacts of various materials have appeared, such as W-Cu series contact materials, Cu -Cr series contact materials, contact materials containing rare earth elements (such as the rare earth elements La, Ce added to Cu-Bi, Cu-Pb alloys), low surge contact materials (such as Co-Ag-Se), and non-toxic Economical Cu-W-Ni-C contact material, etc. However, these materials have their own advantages and disadvantages and their application scope. The copper machining methods of the materials have a great impact on their performance. For example, the comprehensive properties of the composite material obtained after sintering the W framework in advance and then immersed are better than those obtained by direct immersion. Therefore, the choice of process is a prerequisite for obtaining excellent properties of composite materials.
Tungsten copper material for application in electronicsTungsten copper composite materials have the advantages of high strength, good electrical and thermal conductivity, etc. As a new type of electronic packaging materials, they have been favored by electronic engineers and are widely used in power electronic devices (such as rectifiers, thyristors, power modules, laser Diodes, microwave tubes, etc.) and microelectronic devices (such as computer CPU, DSP chips), play an important role in the fields of microwave communication, automatic control, power conversion, aerospace, etc. As an ideal electronic packaging material, it must meet The following basic requirements:
1.The material's thermal conductivity is better, which can timely dissipate the heat generated by the semiconductor during work;
2.The thermal expansion coefficient of the material should match the chips such as Si or GaAs, so as not to damage the thermal stress of the chip;
3.The material must have sufficient strength and stiffness to support and protect the chip;
4.The cost of materials should be as low as possible to meet large-scale commercial applications. In addition, in some special occasions, materials are required to have the characteristics of electromagnetic shielding and radio frequency shielding. Tungsten-copper composites with a tungsten content of 70% to 90% have a thermal expansion coefficient of less than 7 × 10-6 / ℃, while the theoretical thermal conductivity can be as high as 190 ~ 210W / (m · K), which is significantly higher than the traditional pure W , Mo heat sink material, so tungsten copper composite material is a low expansion high thermal conductivity composite material with excellent performance. In addition, the thermal conductivity and thermal expansion of this material are designable and can be adjusted within a certain range as needed.