Molybdenum copper alloy
MoCu alloy is actually a pseudo alloy composed of two immiscible metals, but it has the characteristics of Mo and Cu and has good comprehensive properties. The main characteristics of Mo Cu alloy are as follows:
1. High conductivity and thermal conductivity. In addition to gold, silver, copper and other metals, molybdenum is an element with good conductivity and thermal conductivity. Therefore, molybdenum copper alloy composed of molybdenum and copper has high conductivity and thermal conductivity.
2. Low adjustable coefficient of thermal expansion. The thermal expansion coefficient of copper is higher than that of molybdenum. Therefore, the lower coefficient of thermal expansion can be made according to different composition combination, so that they can match the thermal expansion coefficient of other materials and avoid the thermal stress damage caused by the large difference of thermal expansion coefficient.
3. Special high temperature performance. The melting point of molybdenum is 2 610 ℃, while that of copper is only 1 083 CC. At room temperature and medium temperature, Mo Cu alloy has good strength and plasticity. When the temperature exceeds the melting point of copper, copper in the material can liquefy, evaporate and absorb heat and play a cooling role (sweating cooling). This kind of performance can be used as high temperature materials for special purposes, such as nozzle throat liner resistant to propellant combustion temperature, electrical contact under high temperature arc, etc.
4. No magnetism. Mo and Cu are both non ferromagnetic metals, so Mo Cu alloy is a good non-magnetic material.
5. Low gas content and good vacuum performance. No matter molybdenum or copper, their oxides are very easy to reduce, and their impurities such as N, h, C are easy to remove, so they can keep very low outgassing under vacuum and have good vacuum performance.
6. Good machinability. Because of its high hardness and brittleness, it is difficult to machine pure molybdenum. Because of the decrease of hardness and the increase of plasticity, Mo Cu alloy is beneficial to machining and can be processed into complex shape parts.
Because of these properties, Mo Cu alloy has a broad application prospect. It mainly includes: 1) vacuum contact is being widely used in China; 2) conductive heat dissipation element can meet the requirements of high conductivity, thermal conductivity, heat resistance, vacuum performance and constant thermal expansion coefficient of high-power integrated circuits and microwave devices; 3) as some special instrument components, it can meet the requirements of non-magnetic, constant thermal expansion coefficient, high elastic modulus and high thermal expansion coefficient It can also replace molybdenum as parts of other weapons, such as extended range gun, etc.; 5) it can be used as a reinforcing rib of solid dynamic seal and sliding friction, water-cooled electrode head of high-temperature furnace, and electric processing electrode, etc. Its application can be further developed.
Molybdenum and molybdenum alloy are one of the important materials indispensable for the development of modern science and technology. It can be predicted that the application of molybdenum alloy as a functional material will become a research hotspot for a long time in the future. However, some experts pointed out that in order to expand its application in high-temperature structural materials, it is necessary to solve the problem of high-temperature oxidation.
