U.S. patent number RE31,180 [Application Number 06/280,539] was granted by the patent office on 1983-03-15 for quaternary spinodal copper alloys.
This patent grant is currently assigned to Bell Telephone Laboratories, Incorporated. Invention is credited to John T. Plewes.
United States Patent |
RE31,180 |
Plewes |
March 15, 1983 |
Quaternary spinodal copper alloys
Abstract
Copper alloys are disclosed which contain nickel and tin and Fe,
Zn, Mn, Zr, Nb, Cr, Al, or Mg in amounts within specified limits.
When cold worked and aged according to a critical schedule these
alloys develop a predominantly spinodal structure which renders
them strong as well as ductile. The disclosed alloys are useful,
for example, in the manufacture of components of electrical
apparatus such as springs, connectors and relay elements.
Inventors: |
Plewes; John T. (Berkeley
Heights, NJ) |
Assignee: |
Bell Telephone Laboratories,
Incorporated (Murray Hill, NJ)
|
Family
ID: |
26960350 |
Appl.
No.: |
06/280,539 |
Filed: |
July 6, 1981 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
685263 |
May 11, 1976 |
04052204 |
Oct 4, 1977 |
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Current U.S.
Class: |
148/412; 148/414;
420/470; 420/473; 420/485 |
Current CPC
Class: |
C22F
1/08 (20130101) |
Current International
Class: |
C22F
1/08 (20060101); C22C 009/02 (); C22C 009/06 ();
C22F 001/08 () |
Field of
Search: |
;75/154,159
;148/12.7C,32.5,160 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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09-5064 |
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1934 |
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JP |
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39-19890 |
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1964 |
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JP |
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48-37888 |
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1973 |
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JP |
|
Other References
Wise E., et al., Strength and Aging of Nickel Bronzes, in Metals
Tech, Feb. 1964, pp. 218-244. .
Fetz; E., Bronzen Auf Kupfer-Nickel-Zinn Basis, in Zeit. fur Met.,
vol. 28, May 1936, pp. 350-353. .
Patton, A., Thickness v. Mechanical Properties of CU--Ni--Sn Alloy,
in Brit. Found, Mar. 1962, pp. 129-135..
|
Primary Examiner: Skiff; Peter K.
Attorney, Agent or Firm: Businger; Peter A.
Claims
What is claimed is:
1. Cold worked and aged spinodal copper alloys consisting
essentially of nickel in an amount of from 2-20%, tin in an amount
of from 2-8%, an additional element selected from the group
consisting of Fe in an amount of from 2 to 15%.[., Zn in an amount
of from 2 to 10%,.]. and Mn in an amount of from 2 to 15%, and
remainder copper.
2. Copper alloys of claim 1 and containing at least 5% of an
element selected from said group.
3. Copper alloys of claim 1 containing at least two elements
selected from said group in a combined amount of at most 15%.
4. Cold-worked and aged spinodal copper alloys consisting
essentially of nickel in an amount of from 2-20%, tin in an amount
of from 2-8%, at least one additional element selected from the
group consisting of Zr in an amount of from 0.05-0.2%, Nb in an
amount of from 0.1-0.3%, Cr in an amount of from 0.5-1%, Al in an
amount of from 0.5-1.5%, and Mg in an amount of from 0.5-1%, and
remainder copper.
5. Copper alloys of claim 4 containing at least two elements
selected from said group in a combined amount of at most 1.5%.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention is concerned with spinodal alloys.
2. Description of the Prior Art
Spinodal copper-nickel-tin alloys have been developed recently as
commercially viable substitutes for copper-beryllium and
phosphor-bronze alloys currently prevalent in the manufacture of
articles such as electrical wire, springs, connectors, and relay
elements. U.S. Pat. No. 3,937,638, issued to J. T. Plewes on Feb.
10, 1976, (Case 2) and assigned to the assignee hereof, discloses
copper-nickel-tin alloys which, when cold worked and aged according
to a critical schedule, exhibit unexpectedly high levels of yield
strength in combination with high levels of ductility. For example,
a copper-nickel-tin alloy containing 9% nickel, 6% tin, and
remainder copper, when homogenized, cold worked by an amount
corresponding to an area reduction of 99%, and aged for 75 minutes
at a temperature of 300.degree. C., exhibits a yield strength of
182,000 pounds per square inch and undergoes 52% reduction in
cross-sectional area under tension before failure.
The composition of these alloys is characterized in that such
alloys are in a single phase state at temperatures near the melting
point of the alloy but in a two-phase state at room temperature;
the spinodal structure is characterized in that, at room
temperature, the second phase is finely dispersed throughout the
first phase rather than being situated at the first phase grain
boundaries.
The treatment which develops the spinodal grain structure in
preference to an undesirable second phase precipitation at the
grain boundaries calls for homogenizing, cold working and aging the
alloy. Specifically, the aging temperature is required to be in the
vicinity of an optimal temperature T.sub.d dependent primarily on
the amount of cold work performed but must not exceed the so-called
reversion temperature T.sub.m which is dependent primarily upon the
composition of the alloy. Table I taken from U.S. Pat. No.
3,937,638, shows reversion temperatures for a number of
copper-nickel-tin alloys which develop a spinodal structure when
properly cold worked and aged.
SUMMARY OF THE INVENTION
It has been discovered that the predominantly spinodal two-phase
structure obtained in certain copper-nickel-tin alloys by an
appropriate cold working and aging treatment is essentially
retained in the presence of significant amounts of Fe, Zn, Mn, Zr,
Nb, Cr, Al, or Mg. The addition of such fourth elements is of
interest for reasons such as cost reduction, facilitating hot
working, increasing ductility or strength, and lowering the amount
of cold work required for achieving the spinodal structure.
DETAILED DESCRIPTION
Copper-nickel-tin alloys of a composition containing from 2-20%
nickel, from 2-8% tin, and remainder copper have been found to
develop an essentially spinodal structure even when certain fourth
elements are substituted for corresponding amounts of copper.
While a neutral effect on alloy properties might have reasonably
been foreseen if amounts of up to 2% by weight of Fe, Zn, or Mn
were present in the alloy, it has been ascertained that these
elements may actually be present in amounts in excess of 2% and
that even amounts significantly in excess of 5% can be tolerated.
Specifically, amounts of Fe of up to 15%, of Zn of up to 10%, or of
Mn of up to 15% can replace corresponding amounts of copper in the
interest of reducing the cost of the alloy. If more than one of the
elements Fe, Zn and Mn is present in the alloy, their combined
amount should preferably not exceed 15% by weight. While replacing
copper with Zn or Mn does not significantly change the mechanical
properties of the worked and aged alloy, replacing copper with iron
has, aside from cost reduction, the additional beneficial effect of
increasing formability. Conversely, in the presence of iron smaller
amounts of cold work are sufficient to achieve a desired level of
ductility as compared with the amount required for the
corresponding basic copper-nickel-tin alloy.
In contrast to the relatively large amounts of iron, zinc or
manganese which may beneficially replace copper in spinodal alloys
relatively small amounts of the elements Zr, Nb, Cr, Al or Mg are
recommended. Specifically, Zr added in an amount of from 0.05 to
0.2% by weight prevents surface cracking and alligatoring during
hot working of the cast ingot. The presence of Nb in an amount of
from 0.1 to 0.3% or Cr in an amount of from 0.5 to 1.0% by weight,
enhances ductility of the worked alloy. The presence of Mg in an
amount of from 0.5 to 1.0% or Al in an amount of from 0.5 to 1.5%
by weight leads to an alloy whose properties correspond to those of
copper-nickel-tin alloys of significantly greater tin content.
Since the price of Al or Mg is a fraction of that of tin,
considerable savings can be achieved by their use. If present in
combination the total amount of the elements Zr, Nb, Cr, Al, and Mg
should peferably not exceed 1.5% and, if present in combination
with Fe, Zn, or Mn, the total amount of elements other than Cu, Ni,
and Sn should preferably not exceed 15% by weight.
The effects of the presence of fourth elements were experimentally
investigated at various levels of cold work and corresponding aging
temperatures. To exemplify such effects, Table II shows mechanical
properties of a reference alloy and of four alloys which differ
from the reference alloy in that an amount of a fourth element
replaces a corresponding amount of copper. The reference alloy
contains 9% nickel, 6% tin and remainder copper; the reference
alloy as well as the four quaternary alloys were cold worked by an
amount corresponding to a 35% reduction in area and aged for 20
hours at a temperarture of 350.degree. C. Shown are, for each
alloy, the elastic limit under tension, the area reduction on
fracture under tension and the smallest bend radius achievable
without fracture. It can be seen from Table II that the quaternary
alloys, when compared to the reference alloy, have superior
ductility and formability as measured by area reduction and bend
radius, respectively, and that the strength of these alloys is
comparable or superior to that of the reference alloy.
A second group of examples is shown in Table III. Here too, the
reference alloy contains 9% nickel, 6% tin, and remainder copper;
however, the reference alloy of Table III as well as the quaternary
alloys of examples 5-9 were cold worked by an amount of 99%
reduction in area and aged for 10 minutes at 350.degree. C. It can
be seen from Table III that, except for the alloy containing Al,
the quaternary alloys have properties comparable to those of the
reference alloy. While the aluminum alloy is less ductile that the
reference alloy, its high strength combined with adequate ductility
is indicative of a spinodal structure.
TABLE I ______________________________________ Composition
Reversion Temp (wt. % Ni, Wt. % Sn, Rom. Cu) (T.sub.m)
(.+-.5.degree. C.) ______________________________________ 31/2% Ni
21/2% Sn 401.degree. C. 5% Ni 5% Sn 458.degree. C. 7% Ni 8% Sn
502.degree. C. 9% Ni 6% Sn 508.degree. C. 101/2% Ni 41/2% Sn
530.degree. C. 12% Ni 8% Sn 555.degree. C.
______________________________________
TABLE II ______________________________________ Area Reduction 4th
Element Elastic Limit On Fracture Bend
______________________________________ Reference -- 131,000 psi 6%
15t Ex. 1 9% Fe 131,000 52% 1t Ex. 2 0.2% Nb 144,000 41% 2t Ex. 3
0.7% Cr 128,000 50% 1t Ex. 4 1.5% Mg 151,000 57% 2t
______________________________________
TABLE III ______________________________________ Area Reduction 4th
Element Elastic Limit On Fracture Bend
______________________________________ Reference -- 167,000 psi 50%
2t Ex. 5 5% Zn 160,000 55% 1t Ex. 6 9% Mn 183,000 42% 1t Ex. 7 1%
Mg 191,000 57% 2t Ex. 8 1% Al 210,000 8% 20t Ex. 9 .15% Zr 183,000
40% 4t ______________________________________
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