Abstract
Chromium-copper alloy is a kind of new energy and high technology material formed by a series of chemical reactions with Cu as matrix and chromium and other trace elements added. This page is aimed at introducing what is chromium-copper alloy and some of the important properties, manufacturing methods, and processes of chromium-copper alloy. The safety data sheet of the alloy is also presented. The page can help you know more about the chromium-copper alloy.
This page was built for 5 weeks under the help of my group members, teachers, and the internet.
The important properties of a chromium-copper alloy including price, mechanical properties, fracture properties, thermal properties, electrical properties, processing properties, recycle-ability, and durability.
Keywords: chromium-copper alloy, chromium, metal, electrical contractors
Introduction
Chromium-copper alloy is a kind of heat treatable copper alloy offering good electrical conductivity, thermal conductivity, commonly used as conductive materials. Copper chromium has high hardness, abrasion resistance, and explosion resistance, good uprightness, the thin sheet is uneasy to bent, good crack resistance and high softening temperature [1]. And it is also a kind of material which has huge potential applications and without any special safety concerns.
Literature Review
The composition of chromium-copper alloy is in the range of Cu99-99.04/Cr0.6-1.2 (impurities: Fe<0.1, Si<0.1, Pb<0.1)[2]
Copper Chromium is the primary copper alloy used for resistance spot and seam welding. This alloy achieves good hardness and electrical conductivity through a combination of heat treatment and cold work. It is widely utilized for electrodes, holders, adaptors, as well as numerous electrical applications where resistance to deformation at high temperature is required or when higher mechanical properties are required.[3] The alloy can be manufactured in many ways including soluble infiltration method, powder sintering, mixed casting process, explosive sintering and so on.[4][5]
Because of the Cu-Cr’s special properties, it has been used in many applications, such as Cable, Connector, Electrical Connector, Switch Contacts, Electric Motor, Generator Components, Parts for Electronic Devices, etc.[6]
Properties File
Manufacture Methods
1. Soluble infiltration method[5]
Suitable particle size and purity of Cu powder and Cr powder were put into the mold for pressing, and then it was sintered to make a molten skeleton. With the help of capillary force, Cu was melted into the Cr skeleton to make CuCr composite material (this process needs to be carried out in reducing atmosphere or vacuum).
2. Powder sintering [5]
Chromium powder and copper powder were mixed and pressed in a certain proportion under protective atmosphere, and then sintered to form
3. Mixed casting process [5]
The Cu powder with a low melting point was melted at a temperature higher than the melting point of Cu, and Cr powder with a high melting point was added for mixing.
4. Explosive sintering [5]
After the detonation of the explosive shock wave is produced by the technology reasonable use, and then formed by the container wall cylinder polymerization shock to effect it to powder, and completed in less than a subtle about 6000 ℃ high-temperature loads and unload and 10-50 GPa pressure [9]. Under the action of cylindrical polymerization shock waves, the plasticity of powder particles is relatively large, which leads to pore collapse and even jet formation. At the same time, the local surface temperature is also increased by the deposition of micro-kinetic energy and friction energy on the surface. In addition, because of the instantaneous loading and unloading of shock waves, heat could not be transmitted to the interior of the particles at the first time, but only melted on the surface of the particles, which was then rapidly cooled to form compacted entities with relative density above 90%.
5. Mechanical alloying [4]
Mechanical alloying is a process in which high energy ball mill is used to grind Cu powder and Cr powder in a certain proportion according to a certain ball material ratio for a long time to make the composite powder undergo repeated deformation, cold welding, crushing, re-welding, and re-crushing
6. Laser surface alloying[10]
A layer of Cr powder with a thickness of 100 ~ 300 m adheres to the surface of the shot peening copper matrix with silicate binder, and then the Cr powder is irradiated with a laser beam at a certain speed under the protection of helium, which can be irradiated repeatedly once or several times if necessary. Cr powder and Cu surface layer were rapidly melted and solidified to form Cu -Cr composite material under high energy laser beam irradiation
Processes
The processes that process the alloy into contractors are shown below. The main processes route is: Milling –sintering—rolling--coining.
1. Milling
By milling, the alloy becomes a very fine powder.
2. Sintering
By sintering, causes the powder body to produce granular adhesion, strength, and densification and recrystallization.
3. Rolling [11]
A hardened roll, similar in profile to the thread being manufactured, is placed in contact with the root radius of the tapered thread, and pressure is applied to force the roller to penetrate into the cut surface of the root radius, displacing and cold-forming the thread material.
This deformation cold-works the material, imparting an improved surface finish and compacts and displaces the grains of the root material.
4. Coining
Nano-imprint lithography is to put the plate between the upper and lower die, under the action of pressure to make its material thickness change, and the material outside the extrusion, filling in the mold cavity with undulating fine grain convex, concave, and in the workpiece surface to form undulating drum convex and words or patterns of a forming method.
Reference
[1] Application field of chrome pick copper - construction engineering encyclopedia - cost encyclopedia[EB/OL]. Zjtcn.com, 2019. (2019)[2019 -05 -22]. https://www.zjtcn.com/baike/ggtyyly#catalog_index4.
[2] CES eduPack[M]. Cambridge: Grant, 2018.
[3] Copper Chromium - RWMA Class 2 Copper Alloy C18200 - Cadi[EB/OL]. Cadicompany.com, 2019. (2019)[2019 -05 -22]. http://www.cadicompany.com/products-C18200-copper-chromium.php.
[4] Wang pengju, Chen aihua, wang yinghua, et al. Research progress in preparation methods of copper chromium alloy materials' [J]. Materials guide: nano and new materials, 2016(2):606-609, 4 pages.
[5] Geng hao, liu daqing. Discussion on the preparation method of copper chromium alloy [J]. China metal bulletin, 2017(9).
[6] CuCr/CuCr1-C18200 Chromium Copper,Copper Chromium[EB/OL]. Alb-copperalloys.com, 2019. (2019)[2019 -05 -22]. http://www.alb-copperalloys.com/high-conductivity-copper/c18200/.
[7] Chen wenge, gu chenqing. Manufacturing, application and research progress of electric contact materials [J]. Shanghai electric technology, 1997,(2),12-17
[8] Qian baoguang, geng haoran, guo zhongquan, et al. Research progress and application of electrical contact materials [J]. Mechanical engineering materials, 2004(3):7-9.
[9] Zhang Juan, sun pingquan, li qinwei. Manufacturing technology and properties of CuCr(30) contact materials [J]. Electrical materials, 2016,(6) : 12-14.
[10] Hirose A, Kobayshi K, Surface alloying of copper with chromiun by CO2 laser [J]. Mater sci Eng A,1994, 174(2): 199
[11] What Is Cold Root Rolling | CJWinter[EB/OL]. Coldrootrolling.com, 2019. (2019)[2019 -05 -22]. https://www.coldrootrolling.com/what-is-cold-root-rolling.