Properties of Copper Alloys

Roy Mech. Properties of Copper Alloys. Available online URL http //www.roymech.co.uk/Useful Tables/Matter/Copper Alloys.html. Accessed on July 21, 2007. 

Microstructures and Properties of Copper Alloys after Friction Stir Welding/Processing... 

Bat] Batra, U., Ray, S., Prabhakar, S.R., Tensile Properties of Copper Alloyed Austempered Ductile Iron Effect of Austempering Parameters , J. Mater. Eng. Perform., 13(5), 537-541 (2004) (Phase Relations, Morphology, Experimental, Meehan. Prop., 10)... 

Table 14. Tensile Properties of Dilute Alloy Coppers (C14300—C15720) ...

Typical properties of these alloys are shown in Table 25. In addition, these alloys exhibit notably excellent resistance to stress relaxation at high appHcation temperatures, for instance 200°C, and in this respect outperform beryUium—copper. However, the electrical conductivity of the strongest Cu—Ni—Sn composition (C729) is lower than that of C172. 

Table 8. Properties of Copper and High Copper Alloys...

Properties of copper—tin—lead alloys are Hsted in Table 10. The members of the tin bronze alloy group are cast using the centrifugal, continuous, permanent, plaster, and sand molding methods. Leaded tin—bronze alloys have minimum tensile strengths of 234—248 MPa (34,000—36,000 psi) as cast in sand molds, whereas the minimum tensile strengths for high leaded tin—bronze alloys are 138—207 MPa (20,000—30,000). The values are based on measurement of test bars cast in sand molds. 

Properties of copper—nickel alloys are Hsted in Table 14. The alloys in the copper—nickel group have been successfully cast using the centrifugal, investment, permanent, and sand molding methods. The minimum tensile strengths on test bars cast in sand molds are 207—310 MPa (30,000—45,000 psi). 

Table 14. Properties of Copper-Nickel Alloys and Leaded Nickel Bronze and Brass...

The outstanding properties of copper-base materials are high electrical and thermal conductivity, good durabihty in mildly corrosive chemical environments and excellent ductility for forming complex shapes. As a relatively weak material, copper is often alloyed with zinc (brasses), tin (bronzes), aluminum and nickel to improve its mechanical properties and corrosion resistance. 

This example of aluminium illustrates the importance of the protective him, and hlms that are hard, dense and adherent will provide better protection than those that are loosely adherent or that are brittle and therefore crack and spall when the metal is subjected to stress. The ability of the metal to reform a protective him is highly important and metals like titanium and tantalum that are readily passivated are more resistant to erosion-corrosion than copper, brass, lead and some of the stainless steels. There is some evidence that the hardness of a metal is a signihcant factor in resistance to erosion-corrosion, but since alloying to increase hardness will also affect the chemical properties of the alloy it is difficult to separate these two factors. Thus althou copper is highly susceptible to impingement attack its resistance increases with increase in zinc content, with a corresponding increase in hardness. However, the increase in resistance to attack is due to the formation of a more protective him rather than to an increase in hardness. 

The mechanical properties of wrought alloys depend on composition and metallurgical condition. At the extremes, annealed pure copper has a tensile strength of 180MN m and a hardness of 40 Hy, and heat-treated beryllium copper can have a tensile strength of 1 300 MN m and a hardness of 390 Hy. Summaries of typical properties of some of the more important wrought and cast copper alloys are given in Tables 4.9 and 4.10. 

The choice of alloy for any particular application is determined by the desired physical, mechanical and metallurgical properties. Within these limits, however, a range of materials is usually available. It is essential that at the very earliest stage the choice of materials and the details of design of the installation should be considered from the point of view of corrosion, if the best performance is to be obtained in service. This is particularly true of copper alloys, where protective measures are not normally applied. 

Bimetallic nanoparticles, either as alloys or as core-shell structures, exhibit unique electronic, optical and catalytic properties compared to pure metallic nanopartides [24]. Cu-Ag alloy nanoparticles were obtained through the simultaneous reduction of copper and silver ions again in aqueous starch matrix. The optical properties of these alloy nanopartides vary with their composition, which is seen from the digital photographs in Fig. 8. The formation of alloy was confirmed by single SP maxima which varied depending on the composition of the alloy. 

---