Application Data Sheet:
Mechanical Properties of Copper and Copper Alloys at Low Temperatures

Publist#: 104/5

Copper alloys become stronger and more ductile as temperature goes down. They also retain excellent impact resistance to 20 K. These general characteristics have been revealed in tests on 15 copper alloys, including brasses, bronzes and commercially pure coppers. They were tested by the Cryogenics Div., National Bureau of Standards, for the copper and brass industry to check tensile strength, notch tensile strength, Youngs modulus, and impact properties at temperatures down to 4 K (-454 F). The information presented here is based on a report by R. P. Reed and R. P. Mikesell "Low Temperature Mechanical Properties Of Copper and Selected Copper Alloys," NBS Monograph 101, Institute for Materials Research, National Bureau of Standards, Boulder, Colorado 80302.

Tests — The compositions and condition of these alloys — that is, for standard, commercially available mill stock — are listed in Table 1. Tensile specimens with 1.5 inch gauge lengths provided the data on elastic modulus. Notch tension (also 1.5 inch gauge lengths) and tension tests were conducted using the cryostat and related equipment. Tests were conducted at 295 (ambient), 195, 76, 20, and 4 K. An Instron testing machine was used with a crosshead speed of 0.02 in. per min. Test procedures are described by R.A. Warren and R.P. Reed in NBS Monograph 63.

Results — The figures on the following pages present stress-strain behavior. In Table 2 the average data for each alloy are tabulated for all tests and temperatures. Data spread in most instances was less than ± 1%.

Considerable spread in the impact strength occurred for Copper 102 in the 60% cold-drawn condition. This was related to grain size. Metallographic examination revealed that the specimens with high impact strengths (113 to 115 ft-lb) had small grains while those with low impact strength (57 to 84 ft-lb) had large grains.

Aged Copper Alloy No. 647, although containing only about 2.5 wt. % alloying elements, proved to be considerably stronger than any other alloy tested. Its impact strength remains high, and the notch tensile strength, although falling off at 4 K, is good when compared to the tensile strength. In addition, elongation increases at low temperatures.

Except for the sand cast nickel-aluminum-bronze alloy, all alloys had notched-to-unnotched tensile ratios above one, and good or very good impact properties. Only the sand cast alloy was brittle at low temperature. For most alloys the tensile strength, yield strength, elongation and notch tensile strength increased in the temperature range from 295 to 20 K. Ultimate and yield strengths of most alloys are less at 4 K than at 20 K. Discontinuous yielding is evident in all stress-strain curves at 4 K.

Tables and Figures

Table 1. Condition and Composition of Alloys
Copper and Copper Alloy*ConditionComposition, %
No.NamePbFeSnZnNiP
102 Oxygen Free Cold drawn 60% 4 ppm 4 ppm 1 ppm 4 ppm 1 ppm
122 Phosphorus
Deoxidized,
Annealed 0.0002 0.003 0.00035 0.001 0.028
High Residual
Phosphorus
Cold drawn 26% Same as annealed samples
150 Zirconium
Copper
Annealed, 950 C;
cold drawn 85 to 90%; aged,
450 C, 1 hr
Similar to that of Oxygen Free
with Zr added
220 Commercial
Bronze, 90%
Annealed,
575 C, 3 hr
0.005 0.01 10.01
230 Red Brass, 85% Cold drawn 14% 0.02 15.33
443 Admiralty
Arsenical
Annealed,
575 C, 1 hr
0.04 0.03 0.97 27.56
464 Naval Brass Annealed,
593 C, 1 hr
0.09 0.02 0.63 39.71
510 Phosphor
Bronze, 5% A
Spring cold
drawn 85%
0.02 0.02 4.85 0.05 0.18
614 Aluminum
Bronze D
Commercial
anneal
2.13
647 Copper-nickel
silicon
Aged, 450 C,
2 hr
0.01 1.97
655 High Silicon
Bronze A
Commercial
anneal (soft)
0.01 0.09 0.04
706 Copper Nickel
10%
Annealed,
677 C, 40 min
0.02 1.16 0.07 9.98
715 Copper Nickel
30%
Commercial
anneal
< 0.01 0.59 < 0.01 0.04 30.05
Nickel-
aluminum bronze
Sand cast 3.35 5.20
* Material was 3/4-in. bar, except nickel-aluminum bronze which was a billet.
** 16 ppm Ag; 12 ppm S; 2 ppm As; 5 ppm Sb; less than 3 ppm 0; traces of Au, Bi, Mn, Hg, Cd, Zn
Table 1. Condition and Composition of Alloys (Continued)
Copper and
Copper Alloy*
ConditionOthersHardnessAverage Grain
Diameter, mm
No.Name
102 Oxygen Free Cold drawn 60% ** Rb 45
to 53
0.287
to 2.00
122 Phosphorus
Deoxidized,
Annealed Ag, Bi, Sb, Mn,
As, Ni (trace)
Rf 35 0.051
High Residual
Phosphorus
Cold drawn 26% Rb 50 0.101
150 Zirconium
Copper
Annealed, 950 C;
cold drawn 85 to 90%; aged,
450 C, 1 hr
Zr, 0.18 Rb 68 0.203
220 Commercial
Bronze, 90%
Annealed,
575 C, 3 hr
Rf 49 0.051
230 Red Brass, 85% Cold drawn 14% Ag, Mg (trace) Rf 64 0.025
443 Admiralty
Arsenical
Annealed,
575 C, 1 hr
As, 0.041 Rf 55 0.144
464 Naval Brass Annealed,
593 C, 1 hr
Rb 57 0.036
510 Phosphor
Bronze, 5% A
Spring cold
drawn 85%
Rb 94 0.101
614 Aluminum
Bronze D
Commercial
anneal
Al, 6.57 Rb 97 0.036
647 Copper-nickel
silicon
Aged, 450 C,
2 hr
Rb 98 0.025
655 High Silicon
Bronze A
Commercial
anneal (soft)
Mn, 0.88; Si, 2.90 Rb 54 0.025
706 Copper Nickel
10%
Annealed,
677 C, 40 min
Rb 33 0.051
715 Copper Nickel
30%
Commercial
anneal
Mn, 0.71 to 0.73
Al, < 0.01; As, < 0.01
Rb 47 0.036
Nickel-
aluminum bronze
Sand cast Al, 9.95; Mn, 0.3 Rb 93 0.036
* Material was 3/4-in. bar, except nickel-aluminum bronze which was a billet.
** 16 ppm Ag; 12 ppm S; 2 ppm As; 5 ppm Sb; less than 3 ppm 0; traces of Au, Bi, Mn, Hg, Cd, Zn
Table 2. Average Properties of Copper and Copper Alloys at Low Temperatures
Copper
and Copper Alloy
Test
Temperature,
K
Elastic Properties
No.Name and
Treatment
Youngs
Modulus,
106 psi
(5%)
Shear
Modulus,
106 psi
(2%)
102 Oxygen Free
(Cold drawn
60%)
295
195
76
20
4
17.3

20.0

22.0
122 Phosphorus
Deoxidized,
High Residual
Phosphorus
(Annealed)
295
195
76
20
4
15.1
16.0
16.2
16.3
16.4
6.46
6.81
7.20
7.44
(Cold drawn
26%)
295
195
76
20
4
18.9
19.9
20.3
20.8
21.1
150 Zirconium
Copper
(Cold drawn,
aged)
295
195
76
20
4
15.8

17.2

17.2
220 Commercial
Bronze, 90%
(Annealed)
295
195
76
20
4
15.1
16.4
17.7
18.0
18.1
6.59
6.97
7.24
7.37
230 Red Brass,
85%
(Cold drawn
14%)
295
195
76
20
4
14.9
15.8
17.6
18.1
18.2
6.55
6.77
7.06
7.20
443 Admiralty
Arsenical
(Annealed)
295
195
76
20
4
14.6
14.9
15.5
16.0
16.2
5.94
6.15
6.48
6.55
464 Naval Brass
(Annealed)
295
195
76
20
4
14.0
14.5
14.8
15.0
15.1
5.76
5.94
6.16
6.26
510 Phosphor
Bronze, 5% A
(Cold drawn
85%, spring)
295
195
76
20
4
15.6
16.5
16.7
16.5
16.4
614 Aluminum
Bronze D
(Annealed)
295
195
76
20
4
15.8
16.1
16.3
16.3
16.3
647 Copper-Nickel
Silicon
(Aged)
295
195
76
20
4
21.4
22.3
23.2
23.5
23.6
655 High Silicon
Bronze A
(Annealed,
soft)
295
195
76
20
4
15.6
15.8
16.1
17.0
17.5
706 Copper Nickel
10%
(Annealed)
295
195
76
20
4
17.7

19.5

20.5
715 Copper Nickel
30%
(Annealed)
295
195
76
20
4
22.0

23.0

23.2
Nickel-
Aluminum
Bronze
(Sand cast)
295
195
76
20
4
16.8
17.8
18.5
18.5
18.5
Table 2. Average Properties of Copper and Copper Alloys at Low Temperatures (Continued)
Copper
and Copper Alloy
Test
Temperature,
K
Plastic Properties
Uniaxial
No.Name and
Treatment
Tensile
Strength,
psi
Yield
Strength,
psi
Elongation,
% in 4D
Reduction
of Area,
%
102 Oxygen Free
(Cold drawn
60%)
295
195
76
20
4
48,400
52,900
66,400
74,500
74,600
46,800
49,800
54,400
58,500
58,600
17
20
29
42
41
77
74
78
76
75
122 Phosphorus
Deoxidized,
High Residual
Phosphorus
(Annealed)
295
195
76
20
4
31,300
38,300
50,600
63,800
60,400
6,700
6,600
7,400
8,400
7,900
45
56
62
68
65
76
87
84
83
81
(Cold drawn
26%)
295
195
76
20
4
51,800
56,800
68,400
81,400
81,000
49,400
53,600
59,900
64,100
63,600
17
21
28
46
44
76
79
76
78
72
150 Zirconium
Copper
(Cold drawn,
aged)
295
195
76
20
4
64,450
67,200
77,400
85,200
85,700
59,600
61,300
65,700
66,400
64,700
16
20
26
37
36
62
66
71
72
69
220 Commercial
Bronze, 90%
(Annealed)
295
195
76
20
4
38,500
41,800
55,200
73,200
68,200
9,600
10,200
13,200
15,600
15,000
56
57
86
95
91
84
80
78
73
73
230 Red Brass,
85%
(Cold drawn
14%)
295
195
76
20
4
40,400
46,500
62,000
79,200
71,000
13,000
14,000
16,400
20,900
18,300
48
63
83
80
82
74
79
77
75
71
443 Admiralty
Arsenical
(Annealed)
295
195
76
20
4
44,800
49,600
64,600
76,800
78,600
10,600
12,600
18,700
20,800
21,100
86
91
98
99
92
81
79
73
68
72
464 Naval Brass
(Annealed)
295
195
76
20
4
63,300
67,400
80,400
105,200
99,600
31,000
33,800
38,000
47,600
43,700
37
37
44
41
40
52
54
48
42
48
510 Phosphor
Bronze, 5% A
(Cold drawn
85%, spring)
295
195
76
20
4
77,400
85,600
105,200
131,000
116,400
72,000
78,700
89,200
104,800
100,400
18
20
34
39
34
78
78
67
62
58
614 Aluminum
Bronze D
(Annealed)
295
195
76
20
4
83,200
89,500
105,800
126,400
134,500
59,400
64,800
69,500
80,600
82,400
40
45
52
48
52
66
71
64
58
59
647 Copper-Nickel
Silicon
(Aged)
295
195
76
20
4
112,400
119,400
123,600
133,700
135,800
105,000
110,800
114,100
118,400
119,800
15
18
24
33
31
60
66
70
68
65
655 High Silicon
Bronze A
(Annealed,
soft)
295
195
76
20
4
61,400
69,900
89,000
108,900
101,200
24,200
26,800
31,900
37,600
36,900
66
68
71
72
71
79
79
69
69
70
706 Copper Nickel
10%
(Annealed)
295
195
76
20
4
49,600
54,700
72,000
82,500
80,600
21,400
24,700
24,800
30,200
24,900
37
42
50
50
53
79
77
77
73
73
715 Copper Nickel
30%
(Annealed)
295
195
76
20
4
57,800
68,000
89,800
103,100
104,600
18,700
22,200
31,600
38,100
40,100
47
48
52
51
48
68
70
70
66
65
Nickel-
Aluminum
Bronze
(Sand cast)
295
195
76
20
4
101,200
104,600
117,100
126,600
130,500
44,000
47,800
54,900
61,600
60,100
11
9
6
6
6
9
9
7
2
5
Table 2. Average Properties of Copper and Copper Alloys at Low Temperatures (Continued)
Copper
and Copper Alloy
Test
Temperature,
K
Plastic Properties
Triaxial
No.Name and
Treatment
Notch
Tensile
Strength
(KT 5.0),
psi
Impact
Charpy
Energy
Absorbed,
ft-lb
102 Oxygen Free
(Cold drawn
60%)
295
195
76
20
4
75,700
82,200
93,600
102,400
100,600
96
101
95
84
122 Phosphorus
Deoxidized,
High Residual
Phosphorus
(Annealed)
295
195
76
20
4
43,300
50,400
62,300
72,000
74,700
11
112
112
118
(Cold drawn
26%)
295
195
76
20
4
81,000
86,800
99,800
108,600
109,300
112
112
112
119
150 Zirconium
Copper
(Cold drawn,
aged)
295
195
76
20
4
97,600
103,100
112,400
119,000
121,600
89
105
114
114
220 Commercial
Bronze, 90%
(Annealed)
295
195
76
20
4
49,900
55,600
69,200
76,300
78,900
112
114
112
115
230 Red Brass,
85%
(Cold drawn
14%)
295
195
76
20
4
53,900
58,500
71,200
72,000
74,900
96
82
78
76
443 Admiralty
Arsenical
(Annealed)
295
195
76
20
4
53,800
58,800
75,200
89,400
86,200
112
113
114
114
464 Naval Brass
(Annealed)
295
195
76
20
4
74,700
84,800
100,700
113,900
115,400
38
42
38
35
510 Phosphor
Bronze, 5% A
(Cold drawn
85%, spring)
295
195
76
20
4
136,500
147,100
167,000
185,000
185,400
106
82
54
51
614 Aluminum
Bronze D
(Annealed)
295
195
76
20
4
122,500
133,300
148,100
174,300
160,800
110
100
72
66
647 Copper-Nickel
Silicon
(Aged)
295
195
76
20
4
189,700
194,800
204,600
255,800
212,200
110
106
109
116
655 High Silicon
Bronze A
(Annealed,
soft)
295
195
76
20
4
81,200
92,000
110,700
126,300
122,100
112
112
114
116
706 Copper Nickel
10%
(Annealed)
295
195
76
20
4
65,000
73,100
87,200
96,800
100,000
114
113
115
116
715 Copper Nickel
30%
(Annealed)
295
195
76
20
4
79,400
90,500
112,900
127,600
130,500
115
114
114
114
Nickel-
Aluminum
Bronze
(Sand cast)
295
195
76
20
4
105,200
112,800
118,900
121,800
118,400
10
8
6
6
Copper No. 102 (Cold drawn 60%) Copper No.122 (Annealed) Copper Alloy No. 220 (Annealed) Copper Alloy No. 230 (Cold drawn 14%) Copper No. 122 (Cold drawn 26%) Copper No. 150 (Cold drawn and aged) Copper Alloy No.443 (Annealed) Copper Alloy No. 464 (Annealed) Copper Alloy No. 510 (Cold drawn 85%) Copper Alloy No. 614 (Annealed) Copper Alloy No.706 ( Annealed) Copper Alloy No. 715 (Annealed) Copper Alloy No. 647 (Aged) Copper Alloy No. 655 (Annealed) Copper-Nickel-Aluminium Alloy (Sand cast)