List of copper alloys

Example of a copper alloy object: a Neo-Sumerian foundation figure of Gudea, circa 2100 BC, made in the lost-wax cast method, overall: 17.5 x 4.5 x 7.3 cm, probably from modern-day Iraq, now in the Cleveland Museum of Art (Cleveland, Ohio, USA)

Copper alloys are metal alloys that have copper as their principal component. They have high resistance against corrosion. Of the large number of different types, the best known traditional types are bronze, where tin is a significant addition, and brass, using zinc instead. Both of these are imprecise terms. Latten is a further term, mostly used for coins with a very high copper content. Today the term "copper alloy" tends to be substituted for all of these, especially by museums. ^[1]

Copper deposits are abundant in most parts of the world (globally 70 parts per million), and it has therefore always been a relatively cheap metal. By contrast, tin is relatively rare (2 parts per million), and in Europe and the Mediterranean region, even in prehistoric times, it had to be traded considerable distances and was expensive, sometimes virtually unobtainable. Zinc is even more common at 75 parts per million but is harder to extract from its ores. Bronze with the ideal percentage of tin was therefore expensive, and the proportion of tin was often reduced to save cost. The discovery and exploitation of the Bolivian tin belt in the 19th century made tin far cheaper, although forecasts for future supplies are less positive.

There are as many as 400 different copper and copper alloy compositions loosely grouped into the categories: copper, high copper alloy, brasses, bronzes, cupronickel, copper–nickel–zinc (nickel silver), leaded copper, and special alloys.

Composition

The similarity in external appearance of the various alloys, along with the different combinations of elements used when making each alloy, can lead to confusion when categorizing the different compositions. The following table lists the principal alloying element for four of the more common types used in modern industry, along with the name for each type. Historical types, such as those that characterize the Bronze Age, are vaguer, as the mixtures were generally variable.

Classification of copper and its alloys

Family	Principal alloying element	UNS numbers
Copper alloys, brass	Zinc (Zn)	C1xxxx–C4xxxx,C66400–C69800
Phosphor bronze	Tin (Sn)	C5xxxx
Aluminium bronzes	Aluminium (Al)	C60600–C64200
Silicon bronzes	Silicon (Si)	C64700–C66100
Cupronickel, nickel silvers	Nickel (Ni)	C7xxxx

Mechanical properties of common copper alloys ^[2]

Name	Nominal composition (percentages)	Form and condition	Yield strength (0.2% offset, ksi)	Tensile strength (ksi)	Elongation in 2 inches (percent)	Hardness (Brinell scale)	Comments
Copper (ASTM B1, B2, B3, B152, B124, R133)	Cu 99.9	Annealed	10	32	45	42	Electrical equipment, roofing, screens
		Cold-drawn	40	45	15	90
		Cold-rolled	40	46	5	100
Gilding metal (ASTM B36)	Cu 95.0, Zn 5.0	Cold-rolled	50	56	5	114	Coins, bullet jackets
Cartridge brass (ASTM B14, B19, B36, B134, B135)	Cu 70.0, Zn 30.0	Cold-rolled	63	76	8	155	Good for cold-working; radiators, hardware, electrical, drawn cartridge cases.
Phosphor bronze (ASTM B103, B139, B159)	Cu 89.75, Sn 10.0, P 0.25	Spring temper	—	122	4	241	High fatigue-strength and spring qualities
Yellow or High brass (ASTM B36, B134, B135)	Cu 65.0, Zn 35.0	Annealed	18	48	60	55	Good corrosion resistance
		Cold-drawn	55	70	15	115
		Cold-rolled (HT)	60	74	10	180
Manganese bronze (ASTM 138)	Cu 58.5, Zn 39.2, Fe 1.0, Sn 1.0, Mn 0.3	Annealed	30	60	30	95	Forgings
		Cold-drawn	50	80	20	180
Naval brass (ASTM B21)	Cu 60.0, Zn 39.25, Sn 0.75	Annealed	22	56	40	90	Resistance to salt corrosion
		Cold-drawn	40	65	35	150
Muntz metal (ASTM B111)	Cu 60.0, Zn 40.0	Annealed	20	54	45	80	Condenser tubes
Aluminium bronze (ASTM B169 alloy A, B124, B150)	Cu 92.0, Al 8.0	Annealed	25	70	60	80	—
		Hard	65	105	7	210
Beryllium copper (ASTM B194, B196, B197)	Cu 97.75, Be 2.0, Co or Ni 0.25	Annealed, solution-treated	32	70	45	B60 (Rockwell)	Electrical, valves, pumps, oilfield tools, aerospace landing gears, robotic welding, mold making [3]
		Cold-rolled	104	110	5	B81 (Rockwell)
Free-cutting brass	Cu 62.0, Zn 35.5, Pb 2.5	Cold-drawn	44	70	18	B80 (Rockwell)	Screws, nuts, gears, keys
Nickel silver (ASTM B122)	Cu 65.0, Zn 17.0, Ni 18.0	Annealed	25	58	40	70	Hardware
		Cold-rolled	70	85	4	170
Nickel silver (ASTM B149)	Cu 76.5, Ni 12.5, Pb 9.0, Sn 2.0	Cast	18	35	15	55	Easy to machine; ornaments, plumbing [4]
Cupronickel (ASTM B111, B171)	Cu 88.35, Ni 10.0, Fe 1.25, Mn 0.4	Annealed	22	44	45	–	Condenser, salt-water pipes
		Cold-drawn tube	57	60	15	–
Cupronickel	Cu 70.0, Ni 30.0	Wrought	–	–	–	–	Heat-exchange equipment, valves
Ounce metal [5] Copper alloy C83600 (also known as "Red brass" or "composition metal") (ASTM B62)	Cu 85.0, Zn 5.0, Pb 5.0, Sn 5.0	Cast	17	37	25	60	—
Gunmetal (known as "red brass" in US)	Varies Cu 80-90%, Zn <5%, Sn ~10%, +other elements@ <1%

Mechanical properties of Copper Development Association (CDA) copper alloys ^[6]

Family	CDA	Tensile strength [ksi]		Yield strength [ksi]		Elongation (typ.) [%]	Hardness [Brinell 10 mm-500 kg]	Machinability [YB = 100]
		Min.	Typ.	Min.	Typ.
Red brass	833		32		10	35	35	35
	836	30	37	14	17	30	50–65	84
	838	29	35	12	16	25	50–60	90
Semi-red brass	844	29	34	13	15	26	50–60	90
	848	25	36	12	14	30	50–60	90
Manganese bronze	862	90	95	45	48	20	170–195†	30
	863	110	119	60	83	18	225†	8
	865	65	71	25	28	30	130†	26
Tin bronze	903	40	45	18	21	30	60–75	30
	905	40	45	18	22	25	75	30
	907	35	44	18	22	20	80	20
Leaded tin bronze	922	34	40	16	20	30	60–72	42
	923	36	40	16	20	25	60–75	42
	926	40	44	18	20	30	65–80	40
	927	35	42		21	20	77	45
High-leaded tin bronze	932	30	35	14	18	20	60–70	70
	934	25	32		16	20	55–65	70
	935	25	32	12	16	30	55–65	70
	936	33	30	16	21	15	79-83	80
	937	25	35	12	18	20	55–70	80
	938	25	30	14	16	18	50–60	80
	943	21	27		13	10	42–55	80
Aluminium bronze	952	65	80	25	27	35	110–140†	50
	953	65	75	25	27	25	140†	55
	954	75	85	30	35	18	140–170†	60
	955	90	100	40	44	12	180–200†	50
	958	85	95	35	38	25	150-170†	50
Silicon bronze	878	80	83	30	37	29	115	40
† Brinell scale with 3000 kg load

Comparison of copper alloy standards ^[6]

Family	CDA	ASTM	SAE	SAE superseded	Federal	Military
Red brass	833
	836	B145-836	836	40	QQ-C-390 (B5)	C-2229 Gr2
	838	B145-838	838		QQ-C-390 (B4)
Semi-red brass	844	B145-844			QQ-C-390 (B2)
	848	B145-848			QQ-C-390 (B1)
Manganese bronze	862	B147-862	862	430A	QQ-C-390 (C4)	C-2229 Gr9
	863	B147-863	863	430B	QQ-C-390 (C7)	C-2229 Gr8
	865	B147-865	865	43	QQ-C-390 (C3)	C-2229 Gr7
Tin bronze	903	B143-903	903	620	QQ-C-390 (D5)	C-2229 Gr1
	905	B143-905	905	62	QQ-C-390 (D6)
	907		907	65
Leaded tin bronze	922	B143-922	922	622	QQ-C-390 (D4)	B-16541
	923	B143-923	923	621	QQ-C-390 (D3)	C-15345 Gr10
	926		926
	927		927	63
High-leaded tin bronze	932	B144-932	932	660	QQ-C-390 (E7)	C-15345 Gr12
	934				QQ-C-390 (E8)	C-22229 Gr3
	935	B144-935	935	66	QQ-C-390 (E9)
	937	B144-937	937	64	QQ-C-390 (E10)
	938	B144-938	938	67	QQ-C-390 (E6)
	943	B144-943	943		QQ-C-390 (E1)
Aluminium bronze	952	B148-952	952	68A	QQ-C-390 (G6)	C-22229 Gr5
	953	B148-953	953	68B	QQ-C-390 (G7)
	954	B148-954	954		QQ-C-390 (G5)	C-15345 Gr13
	955	B148-955	955		QQ-C-390 (G3)	C-22229 Gr8
	958				QQ-C-390 (G8)
Silicon bronze	878	B30	878

The following table outlines the chemical composition of various grades of copper alloys.

Chemical composition of copper alloys ^{[6] [7]}

Family	CDA	AMS	UNS	Cu [%]	Sn [%]	Pb [%]	Zn [%]	Ni [%]	Fe [%]	Al [%]	Other [%]
Red brass	833		C83300	93	1.5	1.5	4
			C83400 [8]	90			10
	836	4855B	C83600	85	5	5	5
	838		C83800	83	4	6	7
Semi-red brass	844		C84400	81	3	7	9
	845		C84500	78	3	7	12
	848		C84800	76	3	6	15
Manganese bronze			C86100 [9]	67	0.5		21		3	5	Mn 4
	862†		C86200	64			26		3	4	Mn 3
	863†	4862B	C86300	63			25		3	6	Mn 3
	865	4860A	C86500	58	0.5		39.5		1	1	Mn 0.25
Tin bronze	903		C90300	88	8		4
	905	4845D	C90500	88	10	0.3 max	2
	907		C90700	89	11	0.5 max	0.5 max
Leaded tin bronze	922		C92200	88	6	1.5	4.5
	923		C92300	87	8	1 max	4
	926	4846A	C92600	87	10	1	2
	927		C92700	88	10	2	0.7 max
High-leaded tin bronze	932		C93200	83	7	7	3
	934		C93400	84	8	8	0.7 max
	935		C93500	85	5	9	1	0.5 max
	937	4842A	C93700	80	10	10		0.7 max
	938		C93800	78	7	15		0.75 max
	943	4840A	C94300	70	5	25		0.7 max
Aluminium bronze	952		C95200	88					3	9
	953		C95200	89					1	10
	954	4870B 4872B	C95400	85					4	11
			C95410 [10]	85					4	11	Ni 2
	955		C95500	81				4	4	11
			C95600 [11]	91						7	Si 2
			C95700 [12]	75				2	3	8	Mn 12
	958		C95800	81				5	4	9	Mn 1
Silicon bronze			C87200 [13]	89							Si 4
			C87400 [14]	83			14				Si 3
			C87500 [15]	82			14				Si 4
			C87600 [16]	90			5.5				Si 4.5
	878		C87800 [17]	80			14				Si 4
			C87900 [18]	65			34				Si 1
† Chemical composition may vary to yield mechanical properties

Brasses

Binary Cu Si phase diagram, the base phase diagram for silicon bronzes

Binary Cu Al phase diagram, the base phase diagram for aluminium bronzes, generated using NIMS Open databases https://cpddb.nims.go.jp/cpddb/al-elem/alcu/alcu.htm - DOI https://doi.org/10.48505/nims.3060 and Computherm Pandat https://computherm.com/

Binary Cu Sn phase diagram, the base phase diagram for bronzes, generated using NIMS Open databases https://cpddb.nims.go.jp/cpddb/cu-elem/cusn/cusn.htm - DOI https://doi.org/10.48505/nims.3060 and Computherm Pandat https://computherm.com/

Binary Cu Zn phase diagram, the base phase diagram for brasses, generated using NIMS Open database https://cpddb.nims.go.jp/cpddb/cu-elem/cu_index.htm  Cu-Zn - DOI https://doi.org/10.48505/nims.3060 and Computherm Pandat https://computherm.com/

Main article: Brass

Brass is an alloy of copper with zinc. Brasses are usually yellow in color. The zinc content can vary between few % to about 40%; as long as it is kept under 15%, it does not markedly decrease the corrosion resistance of copper.

Brasses can be sensitive to selective leaching corrosion under certain conditions, when zinc is leached from the alloy (dezincification), leaving behind a spongy copper structure.

• Nordic Gold

Bronzes

Main article: Bronze

A bronze is an alloy of copper and other metals, most often tin, but also alumnium and silicon.

• Aluminium bronzes are alloys of copper and aluminum. The content of aluminum ranges mostly between 5% and 11%. Iron, nickel, manganese and silicon are sometimes added. They have higher strength and corrosion resistance than other bronzes, especially in marine environments, and have low reactivity to sulf ur compounds. Aluminum forms a thin passivation layer on the surface of the metal.
• Bell metal
• Brastil ^{[19] [20]}
• Phosphor bronze
• Nickel bronzes, e.g. nickel silver and cupronickel
• Speculum metal
• UNS C69100

Precious metal alloys

Copper is often alloyed with precious metals like gold (Au) and silver (Ag).

Name	Cu [%]	Au [%]	Ag [%]	Other [%]
Auricupride	†	†
Ashtadhatu	†	†	†	Fe†, Hg†, Sn†, Zn†
Billon	†		†	Hg†
Chinese silver	58		2	17.5 Zn, 11.5 Ni,
Corinthian bronze	†	†	†
CuSil	28		72
Dymalloy	20		80	C (type I diamond)
Electrum, Green gold	6-23	75-80	0-15	0-4 Cd
Grey gold	†	†		Mn†
Guanín	25	56	18
Hepatizon	†	trace	trace
Niello	†	†		Pb sulfides†
Panchaloha	†	†	†	Fe†, Sn†, Pb†, Zn†,
Rose, red, and pink gold	20-50	50-75	0-5
Spangold	18-19	76		5-6 Al
Shakudō	90-96	4-10
Shibuichi	40-77	0-1	23-60
Tibetan silver	†		†	Ni†, Sn†
Tumbaga	3-97	3-97
White gold	†	†		Ni†, Zn†

† amount unspecified

High temperature copper alloys

Copper alloys that are resilient at high temperatures and maintain mechanical properties are used in many applications such as heat exchangers, castings, and rocket engines. Copper alloys typically have very high thermal conductivities compared to other structural alloys which give them an advantage when large heat fluxes are involved, as they are better at dissipating heat. ^{[21] [22] [23]} But copper’s melting point is 1085 Celsius, which is lower than most structural alloys. Therefore, to make use of coppers excellent thermal properties at high temperatures, creep needs to be considered. Creep deformation occurs in materials at relatively high stresses and temperatures. It can dominate as a deformation mechanism in materials above ~0.35 of the melting temperature, ^[24] so designing against it is critical for high temperature applications.  The working temperatures of high temperature copper alloys are up to 700 Celsius. ^{[22] [22] [23]} Most of the leading high temperature copper alloys rely on oxide dispersion strengthening (ODS) or precipitation hardening (PH). ^[21] Some alloys use different methods however, such as alloy, GRCop-84, which takes advantage of intermetallic compounds that form, in its microstructure. These precipitates pin the grains and inhibit grain boundary sliding. ^[22] The advantage of ODS strengthening is that the oxides will not coarsen during temperature aging while PH alloys will, and the strengthening will be lost. ^[21] In all cases, the goal of the strengthening mechanisms are to slow down creep deformation, and the various mechanisms that contribute to it such as dislocation glide, dislocation glide, and vacancy diffusion. Some examples of how these strengthening mechanisms work are by increasing the activation energy needed for lattice and grain boundary diffusion, introducing a threshold stress needed to climb or shear particles in matrix, or by pinning grains which inhibits grain boundary sliding. ^{[25] [21] [23] [22]} Other factors to be considered at high temperature are oxidation and thermomechanical fatigue which may contribute material degradation. ^{[21] [22]}

See also

• Copper-clad steel
• Copper alloys in aquaculture
• Antimicrobial copper-alloy touch surfaces
• Lubaloy C41100

References

1. British Museum, "Scope Note" for "copper alloy"
2. Lyons, William C. and Plisga, Gary J. (eds.) Standard Handbook of Petroleum & Natural Gas Engineering, Elsevier, 2006
3. National Bronze & Metals | Beryllium Copper
4. Lewis Brass & Company | Copper Alloy Data Archived 2021-05-12 at the Wayback Machine
5. Cast copper alloy C83600 (Ounce Metal) substech.com
6. Industrial Investment Castings - Franklin Bronze , retrieved 2009-09-07.
7. Brass and Bronze Alloys, archived from the original on 2009-08-25, retrieved 2009-09-08.
8. UNS C83400 , retrieved 2009-09-08.
9. UNS C86100 , retrieved 2009-09-08.
10. UNS C95410 , retrieved 2009-09-08.
11. UNS C95600 , retrieved 2009-09-08.
12. UNS C95700 , retrieved 2009-09-08.
13. UNS C87200 , retrieved 2009-09-08.
14. UNS C87400 , retrieved 2009-09-08.
15. UNS C87500 , retrieved 2009-09-08.
16. UNS C87600 , retrieved 2009-09-08.
17. UNS C87800 , retrieved 2009-09-08.
18. UNS C87900 , retrieved 2009-09-08.
19. "Doehler-Jarvis Company Collection, MSS-202".
20. Woldman’s Engineering Alloys, 9th Edition 1936, American Society for Metals, ISBN   978-0-87170-691-1
21. Li, G., Thomas, B. G., & Stubbins, J. F. (2000). Modeling Creep and Fatigue of Copper Alloys. Technical Report, Continuous Casting Consortium, University of Illinois at Urbana–Champaign. Available online.
22. Ellis, David L. (2005). GRCop-84: A High-Temperature Copper Alloy for High-Heat-Flux Applications. NASA Glenn Research Center, Cleveland, Ohio. NASA/TM-2005-213582. Available at: https://ntrs.nasa.gov/api/citations/20050123582/downloads/20050123582.pdf
23. Broyles, C. E.; Arzt, E.; Kraft, R. W. (1996). "Creep Deformation of Dispersion-Strengthened Copper."Metallurgical and Materials Transactions A, 27 (11): 3539–3547. doi:10.1007/BF02649859.
24. Creep (deformation).” Wikipedia: The Free Encyclopedia. Wikimedia Foundation, last modified [date you accessed]. https://en.wikipedia.org/wiki/Creep_(deformation)
25. Marquis, E. A.; Dunand, D. C. (2002). “Model for creep threshold stress in precipitation-strengthened alloys with coherent particles.” Scripta Materialia, 47 (8), 503–508. doi:10.1016/S1359-6462(02)00165-3. Northwestern Scholars+1

Bibliography

• Oberg, Erik; Jones, Franklin D.; Horton, Holbrook L. (1992). Machinery's Handbook (24 ed.). New York: Industrial Press Inc. p. 501. ISBN   0-8311-2492-X.

External links

• Corrosion tests and standards: application and interpretation
• Copper Development Association
• Copper Binary Phase Diagrams generation code (batch file - http://www.gotrawama.eu/copperNIMS/ramefabio.txt ) using open thermodynamic databases available at NIMS https://cpddb.nims.go.jp/cpddb/periodic.htm and a commercial software, Computherm Pandat, available for free at https://computherm.com/ help for use at https://computherm.com/docs/pandat_manual.pdf Images of the 34 binary phase diagrams are available at http://www.gotrawama.eu/copperNIMS/PNG/