Copper alloys

The material. In Victorian times people washed their clothes in a "cop­per"—a vat or tank of beaten copper sheet, heated over a fire. The device exploited both the high ductility and the thermal conductivity of the mate­rial. Copper has a distinguished place in the history of civilization: it enabled the technology of the Bronze Age (3000-1000 BC). It is used in many forms: as pure copper, as copper-zinc alloys (brasses), as copper-tin alloys (bronzes), and as copper-nickel and copper-beryllium. The designa­tion of copper is used when the percentage of copper is more than 99.3%.

Composition

Cu with up to 40% Zn or 30% Sn, Al or Ni. General properties

Density

8930 –

9140

kg/m3

Price

6.7 –

7.4

USD/kg

Mechanical properties

Young’s modulus

112

– 148

GPa

Yield strength (elastic limit)

30

– 350

MPa

Tensile strength

100

– 400

MPa

Elongation

3

– 50

%

Hardness—Vickers

44

– 180

HV

Fatigue strength at 107 cycles

60

– 130

MPa

Fracture toughness

30

– 90

MPa. m1/2

Thermal properties

Melting point

982 – 1080

°C

Maximum service temperature

180 – 300

°C

Thermal conductor or insulator?

Good conductor

Thermal conductivity

160 – 390

W/m. K

Specific heat capacity

372 – 388

J/kg. K

Thermal expansion coefficient

16.9 – 18

p, strain/°C

Electrical properties

Electrical conductor or insulator?

Good conductor

Electrical resistivity

1.74 – 5.01

pnhm. cm

Copper and brass are exceptionally ductile and can be worked into complex shapes.

Typical uses. Electrical wiring, cables, bus bars, high strength, high conduc­tivity wires and sections, overheads lines, contact wires, resistance-welding electrodes, terminals, high-conductivity items for use at raised temperatures, heat exchangers, coinage, pans, kettles and boilers, plates for etching and engraving, roofing and architecture, cast sculptures, pumps, valves, marine propellers.