How To Judge The Quality Of Tungsten Copper Alloy?
Tungsten copper alloy is a kind of special metal material, through hardness test to reflect the chemical composition of tungsten copper alloy material, of course, with the now detection technology continues to progress, tungsten copper alloy structure and mechanical properties under the difference in heat treatment can also detect, of tungsten copper alloy quality detection application widely.
When detecting tungsten copper alloy hardness and the test parts of the shape and size of the adaptability is strong, and the test efficiency is relatively high, the main is there is a correspondence between the hardness of W-Cu alloy materials, and other physical characteristics. We in tungsten copper alloy, but also to detect metal can resist plastic deformation ability, the test from a certain angle compared to some common, so for tungsten copper alloy test results, we can compared with each other.
Properties
W-Cu composite material is tungsten and copper is mainly composed of a two-phase structure pseudo alloy, metal matrix composite materials. Due to the metals such as copper and tungsten of difference between the larger, and therefore can not be used casting production. In general, the technology of the alloy powder production.
Tungsten copper alloys have a wide range of uses, most of which are used in aerospace, aviation, electronics, power, metallurgy, machinery, sports equipment and other industries. Secondly to used to manufacture of arc ablation resistance of high voltage electric appliance switch contacts and the rocket nozzle throat lining, a tail rudder and other high temperature components, also used as electrode of EDM machining, mold temperature and other thermal conductivity properties and high temperature occasion.
Process introduction
Process flow for preparing tungsten copper alloy by powder metallurgy method is milling and sintering process.
The tungsten copper or molybdenum copper mixed powder was sintered at 1300-1500. Uniform material prepared by the method is not good, there are many closed the gap, density is usually less than 98%, but by adding small amounts of nickel activated sintering, mechanical alloying method or oxides for reduction method preparation of ultrafine and nano powder can improve the sintering activity, so as to increase the relative density of W-Cu and Mo Cu alloy. But the nickel activated sintering of the material electrical and thermal conductivity decreased significantly, mechanical alloying by introducing impurity will also reduce the conductivity of the material; oxide co reduction method for preparing a powder, process cumbersome, inefficient production to mass production.
Injection molding method
High density tungsten alloy was prepared by injection molding method. The manufacturing method is uniform particle size of 1-5 micron nickel powder, copper tungsten powder or powder and grain size of 0.5 micron tungsten powder and 5-15 microns of tungsten powder, infiltrates the 25% - 30% of the organic binder mixture (such as paraffin or poly (methyl acrylate) injection molding, steam cleaning and irradiation in addition to binder, sintering in hydrogen, high density tungsten alloy.
Copper oxide powder method
Copper oxide powder (mixed and milled reduction to Cu) instead of metal copper powder, copper sintered compacts formed in a continuous matrix in tungsten as strengthening the framework. The high expansion group was divided into second components, the powder was sintered at lower temperature. According to the introduction, the use of very fine powder can improve the sintering properties and densification, so that it can reach more than 99%.
Tungsten and molybdenum skeleton infiltration method
The tungsten powder or molybdenum powder is pressed and formed, and sintered into a tungsten and molybdenum skeleton with a certain porosity. This method is suitable for the low copper content of tungsten copper, molybdenum and copper products. Compared with tungsten copper, molybdenum and copper have the advantages of small mass, easy processing, linear expansion coefficient, thermal conductivity, and some major mechanical properties, such as tungsten, copper and so on.
Although the heat resistance is less than that of tungsten copper, it is better than some heat resistant materials, so the application prospect is better. Because the wettability of copper and molybdenum is worse than that of copper, tungsten, especially preparation of low copper content of copper and molybdenum, infiltration after the material's density is low, cause the material of air tightness, conductivity, thermal conductivity meet requires not and its application is limited.
Application
Moderate uniform for the scope of the general, 19.34g/cm3 density is the melting point of tungsten, tungsten copper alloy metal tungsten and copper has the advantages of the high melting point (tungsten melting point for 3410 DEG C, copper 1080 DEG C), high density tungsten copper density is 8.89 g / cm3); copper conductivity and superior performance, tungsten copper alloy (component WCu7 ~WCu50 microstructure resistance, high temperature, high strength, resistance to arc erosion, density, electrical conductivity, thermal conductivity, are widely used in military high temperature resistant materials, high voltage switch with electrical alloy, EDM electrode, Microelectronic Materials for parts and components widely used in aerospace, aviation, electronics, electric power, metallurgy, machinery, sports equipment and other industries.
1. Military high temperature resistant material
Tungsten copper alloy in aerospace as missile and rocket engine nozzle, gas rudder, air rudder, nose cone, main requirements are required to resist high temperature (3000K~5000K), high temperature air scour ability, mainly the use of copper at high temperature volatile formation of transpiration cooling (copper melting point 1083 DEG C), reduce the surface temperature of copper tungsten, to ensure the use under extreme temperature conditions.
2. Electric alloy for high voltage switch
All Tungsten copper alloy in high voltage switch 128kV SF6 circuit breaker oy
WCu/CuCr, and high-voltage vacuum load switch (12kV 40.5kV 1000A), lightning arrester are widely used and high voltage vacuum switch has the advantages of small volume, easy to maintain, use range widely, used in the wet, inflammable, explosive and corrosion environment. The main performance requirements are arc ablation resistance, anti welding, cut-off current, gas content is less, low thermal electron emission ability. In addition to the conventional macro performance requirements, but also to seek the porosity, microstructure and properties, it is necessary to take a special process, vacuum degassing, vacuum infiltration and other complex processes.
3. Electrode for electric machining
EDM early use of copper or graphite electrode, cheap but not antiablative, has been basically replace tungsten copper electrode. The tungsten copper electrode has the advantages of high temperature resistance, high temperature strength, arc erosion resistance, and good heat conduction performance. Application of discharge electrode in EDM electrode, resistance welding electrode and high voltage.
Electrode is characterized by a wide variety of varieties, small batch and more. The tungsten copper material as the electrode of the electric process should have the uniformity of the density and the organization as high as possible.
4.Micro electronic materials
W-Cu electronic packaging and heat sink material, low expansion character, which have both tungsten and copper the characteristics of high thermal conductivity, the thermal expansion coefficient and thermal conductivity properties can be through the adjustment of tungsten copper components and be changed, thus to tungsten copper provides a wider range of applications. Because tungsten copper material has high heat resistance and good thermal conductivity, and the thermal expansion coefficient of silicon, gallium and ceramic materials, it is widely used in semiconductor materials. Suitable for packaging materials, heat sink materials, heat sink materials, ceramic and GaAs base, etc..
Material properties
Tungsten copper alloy copper and tungsten comprehensive advantages of high strength, high specific gravity, high temperature resistance, arc ablation, conductive electrothermal performance, good processing performance. Using high quality tungsten powder and oxygen free copper powder, application of isostatic pressing molding (high temperature sintering of copper infiltrated) to ensure purity and accurate ratio, meticulous organization, excellent performance. Arc breaking performance is good, good conductivity, good thermal conductivity, small thermal expansion.
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