U.S. patent application number 15/522099 was filed with the patent office on 2017-12-07 for metal alloys including copper.
The applicant listed for this patent is Advanced Alloy Holdings PTY LTD. Invention is credited to Lori Bassman, Patrick Conway, Cody Crosby, Michael Ferry, Kevin Laws, Warren McKenzie, Aarthi Sridhar.
Application Number | 20170349975 15/522099 |
Document ID | / |
Family ID | 55856277 |
Filed Date | 2017-12-07 |
United States Patent
Application |
20170349975 |
Kind Code |
A1 |
Laws; Kevin ; et
al. |
December 7, 2017 |
METAL ALLOYS INCLUDING COPPER
Abstract
The present invention relates to metal alloys including
copper.
Inventors: |
Laws; Kevin; (Sydney, New
South Wales, AU) ; Ferry; Michael; (Sydney, New South
Wales, AU) ; Conway; Patrick; (Sydney, New South
Wales, AU) ; McKenzie; Warren; (Sydney, New South
Wales, AU) ; Bassman; Lori; (Claremont, CA) ;
Crosby; Cody; (Los Altos, CA) ; Sridhar; Aarthi;
(Durham, NC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Advanced Alloy Holdings PTY LTD |
Freshwater, New South Wales |
|
AU |
|
|
Family ID: |
55856277 |
Appl. No.: |
15/522099 |
Filed: |
October 27, 2015 |
PCT Filed: |
October 27, 2015 |
PCT NO: |
PCT/AU2015/050670 |
371 Date: |
April 26, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C22C 45/00 20130101;
C22C 2202/02 20130101; C22C 30/02 20130101; C22F 1/16 20130101;
C22C 30/04 20130101; C22F 1/00 20130101; C22C 30/06 20130101; C22C
9/06 20130101 |
International
Class: |
C22C 9/06 20060101
C22C009/06 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 28, 2014 |
AU |
2014904315 |
Claims
1. An alloy consisting of: TABLE-US-00015 Copper 10 to 50 at. %
Nickel 5 to 50 at. % Manganese 5 to 50 at. % Zinc 0 to 50 at. %
Aluminium 0 to 40 at. % Tin 0 to 40 at. % Chromium 0 to 2 at. %
Iron 0 to 2 at. % Cobalt 0 to 2 at. % Lead 0 to 2 at. % Silicon 0
to 25 at. %
and wherein the alloy has entropy of mixing (.DELTA.S.sub.mix) of
at least 1.1R when calculated according to: .DELTA. S mix = - R i =
1 n ( c i lnc i ) ( Equation 1 ) ##EQU00003## where c is the molar
percentage of the ith component and R is the gas constant.
2. An alloy as defined in claim 1, wherein the alloy includes any
one or more of: TABLE-US-00016 Aluminium 1 to 30 at. % Tin 1 to 30
at. % Zinc 1 to 50 at. % Silicon 1 to 25 at. %
3. An alloy of claim 1 consisting of: TABLE-US-00017 Copper 10 to
50 at. % Nickel 5 to 50 at. % Manganese 5 to 50 at. % Chromium 0 to
2 at. % Iron 0 to 2 at. % Cobalt 0 to 2 at. % Lead 0 to 2 at. %,
and one of: Zinc 1 to 50 at. % Aluminium 1 to 40 at. % Tin 1 to 40
at. % or Silicon 1 to 25 at. %
and wherein the alloy has entropy of mixing (.DELTA.S.sub.mix) of
at least 1.1R when calculated according to: .DELTA. S mix = - R i =
1 n ( c i lnc i ) ( Equation 1 ) ##EQU00004## where c is the molar
percentage of the ith component and R is the gas constant.
4. An alloy consisting of copper and three alloying elements
selected from nickel, manganese, zinc, aluminium and tin and
wherein the alloy has entropy of mixing (.DELTA.S.sub.mix) of at
least 1.1R when calculated according to: .DELTA. S mix = - R i = 1
n ( c i lnc i ) ( Equation 1 ) ##EQU00005## where c is the molar
percentage of the ith component and R is the gas constant.
5. An alloy comprising copper and three or more alloying elements
selected from nickel, manganese, zinc, aluminium and tin and
wherein the alloy has entropy of mixing (.DELTA.S.sub.mix) of at
least 1.1R when calculated according to: .DELTA. S mix = - R i = 1
n ( c i lnc i ) ( Equation 1 ) ##EQU00006## where c is the molar
percentage of the ith component and R is the gas constant.
6. The alloy defined in claim 5, wherein the alloy further
comprises one or more alloying elements selected from the group
consisting of: TABLE-US-00018 Chromium 0 to 2 at. % Iron 0 to 2 at.
% Cobalt 0 to 2 at. % Lead 0 to 2 at. % Silicon 0 to 25 at. %
7. The alloy defined in any one of claims 1 to 6, wherein the alloy
has entropy in the range of 1.1R to 2.5R.
8. The alloy defined in any one of claims 1 to 6, wherein the alloy
has entropy in the range of 1.3 to 2.0R.
9. The alloy defined in any one of claims 1 to 8, wherein the
copper, nickel and manganese are present in substantially equal
atomic percentages.
10. The alloy defined in any one of claims 1 to 9, wherein the
alloy consists of [Cu+Mn+Ni] 60 to 95 at. % with the balance being
Al.
11. The alloy defined in any one of claims 1 to 10, wherein the
alloy consists of Cu, Mn, Ni and Al and has an as-cast hardness
(H.sub.V) in the range of 154 to 398.
12. The alloy defined in any one of claims 1 to 9, wherein the
alloy consists of [Cu+Mn+Ni] 75 to 95 at. % with the balance being
Si.
13. The alloy defined in any one of claims 1 to 9 or 12, wherein
the alloy consists of Cu, Mn, Ni and Si and has an as-cast hardness
(H.sub.V) in the range of 187 to 370.
14. The alloy defined in any one of claims 1 to 9, wherein the
alloy consists of [Cu+Mn+Ni] 75 to 95 at. % with the balance being
Sn.
15. The alloy defined in any one of claims 1 to 9 or 14, wherein
the alloy consists of Cu, Mn, Ni and Sn and has an as-cast hardness
(H.sub.V) in the range of 198 to 487.
16. The alloy defined in any one of claims 1 to 9, wherein the
alloy consists of [Cu+Mn+Ni] 50 to 95 at. % with the balance being
Zn.
17. The alloy defined in any one of claims 1 to 9 or 16, wherein
the alloy consists of Cu, Mn, Ni and Zn and has an as-cast hardness
(H.sub.V) in the range of 102 to 253.
18. The alloy defined in any one of claims 1 to 9, wherein the
alloy is a quinary alloy consisting of [Cu+Mn+Ni] 50 to 95 at. %
with the balance being Al and Zn.
19. The alloy defined in any one of claims 1 to 9 or 18, wherein
the alloy consists of Cu, Mn, Ni, Al and Zn and has an as-cast
hardness (H.sub.V) in the range of 200 to 303.
20. The alloy defined in any one of claims 1 to 9, wherein the
alloy is a quinary alloy consisting of [Cu+Mn+Ni] 75 to 90 at. %
with the balance being Al and Sn.
21. The alloy of any one of claims 1 to 9, wherein the alloy is a
quinary alloy consisting of [Cu+Mn+Ni] 50 to <100 at. % with the
balance being Sn and Zn.
22. The alloy defined in any one of claim 1 to 9, wherein the alloy
consists of Cu, Mn, Ni, Al, Zn, Sn and comprises a single phase or
duplex phase brass.
23. The alloy defined in any one of claims 1 to 22, wherein the
alloy has compressive yield strength in the range of 140 to 760
MPa.
24. The alloy defined in any one of claims 1 to 23, wherein the
alloy has strain at compressive failure of <2% to 80%.
Description
TECHNICAL FIELD
[0001] Metal alloys including copper are disclosed. The alloys have
a similar variety of applications to brass and bronze alloys.
BACKGROUND ART
[0002] The current role of typical brasses and bronzes in the world
today is extensive. Some examples include house keys (sometimes
chrome plated), the key-ring they are on, the domestic door hinges,
door knobs and all their internal lock mechanisms, bathroom
fixtures (which are typically chromed or polished brass), clothes
and bags zippers, electronics connection hardware, gears in gear
motors, automotive and personal electronic device bezels, badges,
military munitions and highly corrosion resistant marine fixtures.
Brasses are even the largest constituent of world coin
currencies.
[0003] All brasses and bronzes can be chrome or nickel plated with
ease for further decorative or corrosion resistant
applications.
[0004] Typical brasses consist predominantly of copper and zinc,
with practical alloy compositions being in the range of copper 60
to 80 weight % and zinc 20-40 weight % with minor additions of lead
and aluminium possible (from 1-5 weight %).
[0005] Typical bronzes are generally much higher in copper content
and consist of 90-95 weight % copper, with small additions of tin,
aluminium and sometimes silver.
[0006] It would be advantageous to reduce the cost of components
formed of copper-based alloys in the existing range of
applications. Alternatively, it would be advantageous to extend the
working life of copper-based alloys in the existing applications or
to make copper-based alloys suitable for additional applications by
improving the mechanical properties of copper-based alloys or by
improving corrosion resistance or by reducing the cost to
manufacture copper-based alloys with similar or improved mechanical
or corrosion resistance properties.
[0007] The above references to the background art here and
throughout the specification, including references to bronze and
brass alloys being "typical", do not constitute an admission that
the art forms a part of the common general knowledge of a person of
ordinary skill in the art. The above references are also not
intended to limit the application of the alloys.
SUMMARY OF THE DISCLOSURE
[0008] The applicants have found that substituting a large amount
of copper in typical bronzes and brasses with manganese and nickel
produces alloys with improved mechanical properties. Additionally,
the amounts of copper, nickel, manganese, zinc, aluminium and tin
can be adjusted so that the properties of the alloy can be tailored
to specific applications. Collectively, the copper-based alloys in
accordance with the finding of the applicants are termed `high
entropy brasses` (HEBs) on account of the lower amount of copper
and higher amounts of nickel and manganese compared with typical
brasses and bronzes, together with other alloying elements of tin,
zinc, aluminium and other elements included in the alloys.
[0009] More specifically, there is provided in a first aspect an
alloy comprising, consisting of, or consisting essentially of:
TABLE-US-00001 Copper 10 to 50 at. % Nickel 5 to 50 at. % Manganese
5 to 50 at. % Zinc 0 to 50 at. % Aluminium 0 to 40 at. % Tin 0 to
40 at. % Chromium 0 to 2 at. % Iron 0 to 2 at. % Cobalt 0 to 2 at.
% Lead 0 to 2 at. % Silicon 0 to 25 at. %
and wherein the alloy has entropy of mixing (.DELTA.S.sub.mix) of
at least 1.1R when calculated according to:
.DELTA. S mix = - R i = 1 n ( c i lnc i ) ( Equation 1 )
##EQU00001##
[0010] where c is the molar percentage of the ith component and R
being the gas constant.
[0011] The alloy may contain incidental impurities.
[0012] Alloying with copper, nickel, manganese, zinc, aluminium and
tin allows for the formation of single-phase and/or duplex phase
microstructures (either face-centred cubic structure, face centred
cubic and body centred cubic or body centred cubic) whereby an
alloy's strength, ductility and corrosion resistance can be
controlled. Including these elements, and in particular copper,
nickel and manganese, in amounts that are more even that in typical
brasses and bronzes increases the entropy of the alloy, leading to
greater microstructural stability and contributing to the
enhancement of mechanical, chemical and physical properties.
[0013] Typically these new alloys have one or more of the following
advantages: [0014] exhibit superior mechanical performance and
corrosion resistance compared to typical bronze and brass alloys
[0015] have lower material cost compared to typical bronze and
brass alloys [0016] are lighter than typical bronze and brass
alloys [0017] can be processed in similar ways to typical bronze
and brass alloys [0018] can be chrome or nickel plated--if
necessary
[0019] The HEBs may include amounts of iron, cobalt, chromium, lead
and silicon in amounts selected to have a specific effect on the
properties of the alloy. These alloying elements are, therefore,
another means of tailoring the HEBs to specific applications.
[0020] For example, alloys according to the first aspect may
include any one or more of:
TABLE-US-00002 Aluminium 1 to 30 at. % Tin 1 to 30 at. % Zinc 1 to
50 at. % Silicon 1 to 25 at. %
[0021] In one embodiment, alloys according to the first aspect may
include one of:
TABLE-US-00003 Aluminium 1 to 30 at. % Tin 1 to 30 at. % Zinc 1 to
50 at. % or Silicon 1 to 25 at. %
[0022] There is also provided in a second aspect an alloy
comprising, consisting of, or consisting essentially of copper and
three or more alloying elements selected from nickel, manganese,
zinc, aluminium and tin and wherein the alloy has entropy of mixing
(.DELTA.S.sub.mix) of at least 1.1R when calculated according to
Equation 1.
[0023] The alloy may contain incidental impurities.
[0024] The alloy of the second aspect may include one or more
alloying elements selected from the group comprising or consisting
of:
TABLE-US-00004 Chromium 0 to 2 at. % Iron 0 to 2 at. % Cobalt 0 to
2 at. % Lead 0 to 2 at. % Silicon 0 to 25 at. %
[0025] In an embodiment of the second aspect there is provided an
alloy comprising, consisting of, or consisting essentially of
copper and three alloying elements selected from nickel, manganese,
zinc, aluminium and tin and wherein the alloy has entropy of mixing
(.DELTA.S.sub.mix) of at least 1.1R when calculated according to
Equation 1.
[0026] In another embodiment of the second aspect there is provided
an alloy comprising, consisting of, or consisting essentially
of:
(i) copper and three alloying elements selected from nickel,
manganese, zinc, aluminium and tin, and (ii) chromium 0 to 2 at. %,
iron 0 to 2 at. %, cobalt 0 to 2 at. % and lead 0 to 2 at. %, and
wherein the alloy has entropy of mixing (.DELTA.S.sub.mix) of at
least 1.1R when calculated according to Equation 1.
[0027] In a further embodiment of the second aspect there is
provided an alloy comprising, consisting of, or consisting
essentially of:
(i) copper, nickel and manganese, (ii) one alloying element
selected from zinc, aluminium and tin, and (iii) chromium 0 to 2
at. %, iron 0 to 2 at. %, cobalt 0 to 2 at. % and lead 0 to 2 at.
%, and wherein the alloy has entropy of mixing (.DELTA.S.sub.mix)
of at least 1.1R when calculated according to Equation 1.
[0028] In still a further embodiment of the second aspect there is
provided an alloy comprising, consisting of, or consisting
essentially of:
(i) copper, nickel and manganese, (ii) one alloying element
selected from zinc, aluminium and tin, and wherein the alloy has
entropy of mixing (.DELTA.S.sub.mix) of at least 1.1R when
calculated according to Equation 1.
[0029] In yet another embodiment of the second aspect there is
provided an alloy comprising:
(i) copper, nickel and manganese, (ii) one or more alloying
elements selected from zinc, aluminium and tin, and wherein the
alloy has entropy of mixing (.DELTA.S.sub.mix) of at least 1.1R
when calculated according to Equation 1.
[0030] In another embodiment of the second aspect there is provided
an alloy comprising, consisting of, or consisting essentially of
copper and three alloying elements selected from silicon, nickel,
manganese, zinc, aluminium and tin and wherein the alloy has
entropy of mixing (.DELTA.S.sub.mix) of at least 1.1R when
calculated according to Equation 1.
[0031] In yet another embodiment of the second aspect there is
provided an alloy comprising, consisting of, or consisting
essentially of:
(i) copper and three alloying elements selected from silicon,
nickel, manganese, zinc, aluminium and tin, and (ii) chromium 0 to
2 at. %, iron 0 to 2 at. %, cobalt 0 to 2 at. % and lead 0 to 2 at.
%, and wherein the alloy has entropy of mixing (.DELTA.S.sub.mix)
of at least 1.1R when calculated according to Equation 1.
[0032] In yet another embodiment of the second aspect there is
provided an alloy comprising, consisting of, or consisting
essentially of:
(i) copper, nickel and manganese, (ii) one alloying element
selected from silicon, zinc, aluminium and tin, and (iii) chromium
0 to 2 at. %, iron 0 to 2 at. %, cobalt 0 to 2 at. % and lead 0 to
2 at. %, and wherein the alloy has entropy of mixing
(.DELTA.S.sub.mix) of at least 1.1R when calculated according to
Equation 1.
[0033] In still a further embodiment of the second aspect there is
provided an alloy comprising, consisting of, or consisting
essentially of:
(i) copper, nickel and manganese, (ii) one alloying element
selected from silicon, zinc, aluminium and tin, and wherein the
alloy has entropy of mixing (.DELTA.S.sub.mix) of at least 1.1R
when calculated according to Equation 1.
[0034] There is provided in a third aspect an alloy comprising,
consisting of, or consisting essentially of:
TABLE-US-00005 Copper 10 to 50 at. % Nickel 5 to 50 at. % Manganese
5 to 50 at. % Chromium 0 to 2 at. % Iron 0 to 2 at. % Cobalt 0 to 2
at. % Lead 0 to 2 at. %, and one of: Zinc 1 to 50 at. % Aluminium 1
to 40 at. % Tin 1 to 40 at. % or Silicon 1 to 25 at. %
and wherein the alloy has entropy of mixing (.DELTA.S.sub.mix) of
at least 1.1R when calculated according to Equation 1.
[0035] The alloy may contain incidental impurities.
[0036] In one embodiment alloys according to the third aspect may
comprise, consist of, or consist essentially of:
TABLE-US-00006 Copper 10 to 50 at. % Nickel 5 to 50 at. % Manganese
5 to 50 at. % Chromium 0 to 2 at. % Iron 0 to 2 at. % Cobalt 0 to 2
at. % Lead 0 to 2 at. %, and one of: Zinc 20 to 35 at. % Aluminium
5 to 40 at. % Tin 5 to 25 at. % or Silicon 2.5 to 15 at. %
and wherein the alloy has entropy of mixing (.DELTA.S.sub.mix) of
at least 1.1R when calculated according to Equation 1.
[0037] In another embodiment alloys according to the third aspect
may comprise, consist of, or consist essentially of:
TABLE-US-00007 Copper 10 to 50 at. % Nickel 5 to 50 at. % Manganese
5 to 50 at. % and one of: Zinc 1 to 50 at. % Aluminium 1 to 40 at.
% Tin 1 to 40 at. % or Silicon 1 to 25 at. %
and wherein the alloy has entropy of mixing (.DELTA.S.sub.mix) of
at least 1.1R when calculated according to Equation 1.
[0038] In yet another embodiment alloys according to the third
aspect may comprise, consist of, or consist essentially of:
TABLE-US-00008 Copper 10 to 50 at. % Nickel 5 to 50 at. % Manganese
5 to 50 at. %, and one of: Zinc 20 to 35 at. % Aluminium 5 to 40
at. % Tin 5 to 25 at. % or Silicon 2.5 to 15 at. %
and wherein the alloy has entropy of mixing (.DELTA.S.sub.mix) of
at least 1.1R when calculated according to Equation 1.
[0039] The alloy of the first, second or third aspect may have
entropy in the range of 1.1R to 2.5R. Alternatively, the alloy may
have entropy in the range of 1.3R to 2.0R. By way of comparison,
the entropy of a typical brass or bronze calculated using Equation
1 will be no greater than approximately 0.82R.
[0040] Copper, nickel and manganese may be present in substantially
equal atomic percentages in the alloy of the first, second or third
aspect.
[0041] The alloy of the first, second or third aspect may consist
of, or consist essentially of [Cu+Mn+Ni] 50 to 95 at. % with the
balance being Al.
[0042] The alloy of the first, second or third aspect may consist
of, or consist essentially of [Cu+Mn+Ni] 60 to 95 at. % with the
balance being Al.
[0043] The alloy of the first, second or third aspect may consist
of, or consist essentially of Cu, Mn, Ni and Al and have an as-cast
hardness (H.sub.V) in the range of 154 to 398.
[0044] The alloy of the first, second or third aspect may consist
of, or consist essentially of [Cu+Mn+Ni] 75 to 95 at. % with the
balance being Si.
[0045] The alloy of the first, second or third aspect may consist
of, or consist essentially of [Cu+Mn+Ni] 85 to 97.5 at. % with the
balance being Si.
[0046] The alloy of the first, second or third aspect may consist
of, or consist essentially of Cu, Mn, Ni and Si and have an as-cast
hardness (H.sub.V) in the range of 187 to 370.
[0047] The alloy of the first, second or third aspect may consist
of, or consist essentially of [Cu+Mn+Ni] 60 to 95 at. % with the
balance being Sn.
[0048] The alloy of the first, second or third aspect may consist
of, or consist essentially of [Cu+Mn+Ni] 75 to 95 at. % with the
balance being Sn.
[0049] The alloy of the first, second or third aspect may consist
of, or consist essentially of Cu, Mn, Ni and Sn and have an as-cast
hardness (H.sub.V) in the range of 198 to 487.
[0050] The alloy of the first, second or third aspect may consist
of, or consist essentially of [Cu+Mn+Ni] 50 to 95 at. % with the
balance being Zn.
[0051] The alloy of the first, second or third aspect may consist
of, or consist essentially of [Cu+Mn+Ni] 65 to 80 at. % with the
balance being Zn.
[0052] The alloy of the first, second or third aspect may consist
of, or consist essentially of Cu, Mn, Ni and Zn and have an as-cast
hardness (H.sub.V) in the range of 102 to 253.
[0053] The alloy of the first, second or third aspect may be a
quinary alloy consisting of, or consisting essentially of
[Cu+Mn+Ni] 50 to 95 at. % with the balance being Al and Zn.
[0054] The alloy of the first, second or third aspect may consist
of, or consist essentially of Cu, Mn, Ni, Al and Zn and have an
as-cast hardness (H.sub.V) in the range of 200 to 303.
[0055] An alternative alloy of the first, second or third aspect
may be a quinary alloy consisting of, or consisting essentially of
[Cu+Mn+Ni] 75 to 90 at. % with the balance being Al and Sn.
[0056] An alternative alloy of the first, second or third aspect
may be a quinary alloy consisting of, or consisting essentially of
[Cu+Mn+Ni] 50 to <100 at. % with the balance being Sn and
Zn.
[0057] A further alternative alloy of the first, second or third
aspect may be an alloy consisting of, or consisting essentially of
Cu, Mn, Ni, Al, Zn, Sn and comprise a single phase or duplex phase
brass.
[0058] The alloy of the first, second or third aspect may have
compressive yield strength in the range of 140 to 760 MPa.
Alternatively, the compressive yield strength may be in the range
of 290 to 760 MPa. In a further alternative, the compressive yield
strength may be in the range of 420 to 760 MPa.
[0059] The alloy of the first, second or third aspect may have
strain at compressive failure of <2% to 80%. In an alternative,
the strain at compressive failure may be <2% to 60%. In a
further alternative, the strain at compressive failure may be
<2% to 40%. In yet another alternative, the strain at
compressive failure may be <2% to <5%.
[0060] In a further aspect, there is a provided a casting of an
alloy according to the first, second or third aspect. The casting
may be heat treated.
[0061] The term "alloy" as used throughout this specification
includes a reference to castings. The term also includes within its
scope other metal products having a composition defined according
to the first, second or third aspects defined above.
[0062] Those skilled in the art will appreciate that the alloys
disclosed herein may contain incidental unavoidable impurities.
DESCRIPTION OF EMBODIMENTS
[0063] Test work carried out by the applicants has identified HEBs
as having desirable properties in comparison to the properties of
typical brasses and bronzes. In particular, the HEBs are based on
the realisation by the applicants that the desirable properties are
obtained by replacing a significant portion of copper in typical
brasses and bronzes with manganese and nickel to produce alloys
with considerably higher entropy of mixing (.DELTA.S.sub.mix
according to Equation 1 above) compared with the entropy of mixing
for typical brasses and bronzes.
[0064] A range of typical brass compositions and their associated
mechanical properties are listed in Table 1. Amongst them, the
copper-content ranges from 61 at. % to 85 at. % and the tensile
yield strength ranges from 186 MPa to 315 MPa. It will be
appreciated, however, that tensile yield strength does not vary
linearly with copper-content. These alloys all have entropy of
mixing that is no greater than approximately 0.82R when calculated
according to Equation 1.
TABLE-US-00009 Elongation Alloy Composition Crystal Hardness Yield
.sigma..sub.T (Tensile at. % Structure (Vickers) (MPa) Strain)
Cu.sub.76Zn.sub.19.5Al.sub.4.5 fcc 95 186 55% (Al-Brass)
Cu.sub.61Zn.sub.38.5Sn.sub.0.5 fcc + bcc 146 315 27% (Naval Brass)
Cu.sub.70Zn.sub.30 (C26000) fcc 100 275 43% Cu.sub.85Zn.sub.15
(C23000) fcc 100 270 25% Cu.sub.65Zn.sub.32.5Pb.sub.2.5 fcc 138 310
25% (C35300)
.DELTA. S mix = - R i = 1 n ( c i lnc i ) ( Equation 1 )
##EQU00002##
[0065] The applicants have found that alloys with comparable or
improved mechanical, chemical and physical properties can be
obtained by replacing a significant amount of copper in typical
brasses and bronzes with manganese and nickel and other alloying
elements to produce alloys that have entropy of mixing according to
Equation 1 that is at least 1.1R.
[0066] The alloys may have Cu 10 to 50 at. %, Ni 5 to 50 at. % and
Mn 5 to 50 at. %. The alloys optionally include varying amounts of
Zn (0 to 50 at. %), Sn (0 to 40 at. %), Fe (0 to 2 at. %), Cr (0 to
2 at. %), Pb (0 to 2 at. %), Co (0 to 2 at. %) and Si (0 to 25 at.
%) depending on the desired properties of the alloy. It will be
appreciated, however, that the alloys may include other alloying
elements in amounts alongside Cu, Mn and Ni so that the alloy has
entropy of mixing according to Equation 1 that is at least
1.1R.
[0067] Examples of alloys identified by the applicant were prepared
and tested to determine their properties. The examples are outlined
below. All examples were prepared by the following method.
[0068] A ternary master alloy of substantially equi-atomic Cu, Mn
and Ni was prepared from high purity elements Cu (99.95 wt. %), Ni
(99.95 wt. %) and Mn (99.8 wt. %) using a Buhler MAM1 arc melter in
a Ti-gettered argon (99.999 vol. %) atmosphere. Ingots of the
master alloy were turned and melted five times to ensure a
homogeneous master alloy was achieved. Care was also taken to
ensure a sufficiently low melt superheat as to avoid the
evaporation of Mn.
[0069] Quaternary and quinary alloy ingots containing Zn were
alloyed using an induction furnace by combining the master alloy
with pure Zn (99.99 wt. %) in a boron nitride-coated graphite
crucible. These alloys were heated in a step-wise fashion with
sufficient holding times at 700'C, 900.degree. C. and 1050.degree.
C. to enable the dissolving of the master alloy in Zn in order to
minimise Zn evaporation, yet produce a homogeneous alloy melt. Once
a steady Zn evaporation rate was determined for this alloying
process, excess Zn was added to these alloys to compensate for this
loss. Although the Zn loss through evaporation was less than 20%,
it is expected that industrial-scale production according to
current production processes for alloys including Zn would result
in around 20% loss of Zn during manufacturing.
[0070] Quaternary alloys containing Al or Sn were produced by
adding the balance of Al (99.99 wt. %) or Sn (99.95 wt. %) to the
master alloy, arc melting and vacuum casting into a copper mould to
produce 3 mm diameter rods.
[0071] Once solidified, alloy samples were removed from the mould
and allowed to cool to room temperature. They were then were heat
treated in an elevator furnace at 850.degree. C. for 18 hours under
a circulating argon atmosphere and then quenched in water.
[Cu, Ni, Mn].sub.100-xAl.sub.x Alloy System
[0072] Table 2 below lists six samples of Cu, Ni, Mn, Al alloys and
some key properties.
TABLE-US-00010 TABLE 2 Crystal Structure Hardness (Vickers) Alloy
Heat Heat Yield .sigma..sub.C Comp Composition As-Cast treated
As-Cast Treated (MPa) Strain Magnetic [CuNiMn].sub.95Al.sub.5 fcc
fcc.sub.1 + fcc.sub.2 166 .+-. 12 173 .+-. 2.5 290 60% No
[CuNiMn].sub.90Al.sub.10 fcc.sub.1 + fcc.sub.2 fcc.sub.1 +
fcc.sub.2 241 .+-. 2.5 220 .+-. 4.3 480 40% No
[CuNiMn].sub.80Al.sub.20 fcc.sub.2 + bcc.sub.2 fcc.sub.2 346 .+-.
8.2 355 .+-. 9.1 -- <5% No [CuNiMn].sub.75Al.sub.25 fcc.sub.2 +
bcc.sub.2 bcc.sub.2 377 .+-. 2.1 373 .+-. 4.9 -- <2% Yes
[CuNiMn].sub.70Al.sub.30 fcc.sub.2 + bcc.sub.2 bcc.sub.2 355 .+-.
10.3 359 .+-. 9.5 -- <2% Yes [CuNiMn].sub.60Al.sub.40 bcc.sub.2
+ bcc.sub.3 bcc.sub.3 395 .+-. 2.7 398 .+-. 16.8 -- <2% Yes
[0073] The samples exhibit increasing hardness with increasing
aluminium content. However, even the alloy with the lowest
aluminium content at 5 at. % exhibited higher hardness than any of
the typical brasses listed in Table 1. Furthermore, strength is
comparable with the naval brass and C26000, C23000 and C35300
alloys, but ductility is considerably higher for the same
comparable strength.
[0074] Above 20 at. % aluminium the samples had considerably higher
hardness than the brasses in Table 1, but considerably less
compressive strain. Samples at and above 25 at. % aluminium
exhibited magnetic properties.
[0075] Samples with 10 at. % and 20 at. % aluminium have entropy
according to Equation 1 of 1.314R and 1.379R respectively.
[Cu, Ni, Mn].sub.100-xSi.sub.x Alloy System
[0076] Table 3 below lists four samples of Cu, Ni, Mn, Si alloys
and some key properties.
TABLE-US-00011 TABLE 3 Crystal Structure Hardness (Vickers) Alloy
Composition As-Cast Heat treated As-Cast Heat Treated Magnetic
[CuNiMn].sub.97.5Si.sub.2.5 fcc.sub.1 + bcc.sub.2 fcc.sub.1 +
bcc.sub.2 193 .+-. 6.1 183 .+-. 6.5 Faint [CuNiMn].sub.95Si.sub.5
fcc.sub.1 + bcc.sub.2 fcc.sub.1 + bcc.sub.2 293 .+-. 12.7 250 .+-.
7.1 Yes [CuNiMn].sub.90Si.sub.10 fcc.sub.1 + bcc.sub.2 fcc.sub.1 +
bcc.sub.2 330 .+-. 7.8 334 .+-. 14.4 Yes [CuNiMn].sub.85Si.sub.15
fcc.sub.1 + bcc.sub.2 fcc.sub.1 + bcc.sub.2 -- 376 .+-. 10.4
Yes
[0077] As with the quaternary system including aluminium, the
quaternary system including silicon has higher hardness than the
typical brasses listed in Table 1. However, faint magnetism exists
with even small amounts of silicon.
[Cu, Ni, Mn].sub.100-xSn.sub.x Alloy System
[0078] Table 4 below lists four samples of Cu, Ni, Mn, Sn alloys
and some key properties.
TABLE-US-00012 TABLE 4 Crystal Structure Hardness (Vickers) Alloy
Heat Heat Yield .sigma..sub.C Comp Composition As-Cast treated
As-Cast Treated (MPa) Strain Magnetic [CuNiMn].sub.95Sn.sub.5
fcc.sub.1 + bcc.sub.2 fcc.sub.1 + bcc.sub.2 205 .+-. 7.6 178 .+-.
5.8 420 60% Faint [CuNiMn].sub.90Sn.sub.10 fcc.sub.1 + bcc.sub.2
fcc.sub.1 + bcc.sub.2 318 .+-. 4.2 255 .+-. 16.4 760 20% Yes
[CuNiMn].sub.80Sn.sub.20 fcc + bcc.sub.2 fcc.sub.1 + bcc.sub.2 402
.+-. 1.9 533 .+-. 15.4 brittle Yes [CuNiMn].sub.75Sn.sub.25
bcc.sub.1 + bcc.sub.2 bcc.sub.2 467 .+-. 19.7 507 .+-. 37.0 brittle
Yes
[0079] Results for the quaternary alloy system including tin
exhibits considerably higher hardness and strength compared to the
typical brass alloys listed in Table 1. Relatively small amounts of
tin cause the quaternary alloy system to exhibit magnetism.
[0080] The samples including at least 20 at. % tin had hardness in
excess of 400H.sub.V in the as-cast from and, even then, responded
well to the heat treatment with the result that hardness for both
samples increased to well above 500H.sub.V.
[Cu, Ni, Mn].sub.100-xZn.sub.x Alloy System
[0081] Table 5 below lists four samples of Cu, Ni, Mn, Zn alloys
and some key properties.
TABLE-US-00013 TABLE 5 Crystal Structure Hardness (Vickers) Alloy
Heat Heat Yield .sigma..sub.C Comp Composition As-Cast treated
As-Cast Treated (MPa) Strain Magnetic [CuNiMn].sub.80Zn.sub.20
fcc.sub.1 fcc.sub.1 109 .+-. 7.1 113 .+-. 2.8 140 80% No
[CuNiMn].sub.75Zn.sub.25 fcc.sub.1 fcc.sub.1 147 .+-. 5.9 108 .+-.
9.7 225 55% No [CuNiMn].sub.70Zn.sub.30 fcc.sub.1 fcc.sub.1 118
.+-. 7.4 122 .+-. 4.4 -- No [CuNiMn].sub.65Zn.sub.35 fcc.sub.1 +
bcc.sub.2 fcc.sub.1 + bcc.sub.2 246 .+-. 7.1 248 .+-. 20 -- No
[0082] The zinc-based quaternary alloys did not exhibit magnetic
properties and, below 35 at. % zinc, the alloys exhibited
relatively low hardness compared to other quaternary alloy samples.
However, the samples with relatively low zinc (i.e. 20 at. % and 25
at. % zinc) exhibited relatively high ductility.
[Cu, Ni, Mn].sub.100-x[Al, Sn, Zn].sub.x Alloy System
[0083] Table 6 below lists five samples, one of which consists of
Cu, Ni, Mn, Al, Sn and the remainder consisting of Cu, Ni, Mn, Al,
Zn.
TABLE-US-00014 TABLE 6 Crystal Structure Hardness (Vickers) Alloy
Composition As-Cast Heat treated As-Cast Heat Treated Magnetic
[CuNiMn].sub.90Al.sub.5Si.sub.5 fcc.sub.1 + bcc.sub.2 fcc.sub.1 +
bcc.sub.2 297 .+-. 4.4 303 .+-. 9.4 Yes
[CuNiMn].sub.75Al.sub.5Si.sub.20 fcc.sub.1 + fcc.sub.2 fcc.sub.1 +
fcc.sub.2 250 .+-. 10.8 271 .+-. 8.8 No
[CuNiMn].sub.60Al.sub.5Si.sub.35 fcc.sub.1 + bcc.sub.1 fcc.sub.1 +
bcc.sub.1 295 .+-. 8.5 -- No [CuNiMn].sub.80Al.sub.10Si.sub.10
fcc.sub.1 + bcc.sub.1 fcc.sub.1 + fcc.sub.2 256 .+-. 12.8 -- No
[CuNiMn].sub.70Al.sub.10Si.sub.20 fcc.sub.1 + bcc.sub.2 fcc.sub.1 +
bcc.sub.2 214 .+-. 14.4 -- No
[0084] The hardness for all quinary samples is considerably greater
than the hardness of the typical brasses listed in Table 1. As with
both the tin- and zinc-based quaternary alloys disclosed in Tables
4 and 5, the quinary alloy sample including tin exhibits magnetic
properties, but the quinary alloys including zinc do not. Although
aluminium can cause magnetic properties in the alloys, there is
insufficient aluminium in the quinary alloys to cause magnetic
properties.
[0085] To give these alloys context in terms of entropy, the sample
consisting of [CuNiMn].sub.80Al.sub.10Zn.sub.10 has entropy of
1.518R when calculated according to Equation 1.
[0086] Although the alloys disclosed in Tables 2 to 6 are based on
a master alloy comprising Cu, Ni and Mn in substantially
equi-atomic amounts, the invention is not limited to equi-atomic
amounts of Cu, Mn and Ni. It is contemplated that the relative
amounts of Cu, Ni and Mn in a given alloy will be selected
depending on the properties required for the designated application
of that alloy. The following description addresses some
applications and how the alloy composition might be adjusted to
produce the desired properties for that application.
Alloy Variants by Application
[0087] The above examples are a subset of the full range of
potential HEBs that can be usefully applied by adjusting the alloy
composition to produce desired properties. Examples of the
different application and how the composition would be adjusted are
outlined below.
Reduced Cost Alloys
[0088] Based on 5-year market prices, nickel is more expensive than
copper (around 1% times the price) and manganese is essentially 1/3
the price of copper on a per kilogram basis. Given that the HEBs
involve replacing a significant quantity of copper in brasses and
bronzes with nickel and manganese, savings in terms of raw
materials cost are expected to be 5 to 10% and higher if less
nickel is used in the alloy. For example, an alloy with a lower Ni
and higher Mn content would be considerably cheaper to produce and
display similar strengths to the equal ratio alloy (i.e. Cu, Ni and
Mn in equal atomic amounts), but may work harden faster and will
likely be less corrosion resistant.
Corrosion Resistant
[0089] On the other hand, an alloy with a higher Ni content would
exhibit superior corrosion resistance. Alloys that contained Al
were found to be particularly corrosion resistant. These would be
suited to conditions where high corrosion resistance is imperative
(although the typical brasses already exhibit good corrosion
resistance, it is anticipated that the higher nickel content will
result in HEBs have even better corrosion resistance)--say for
marine applications.
Anti-Bacterial
[0090] It is anticipated that these alloys would have similar
`anti-microbial` properties to conventional brasses. Copper is
known to be highly antimicrobial in a range of environments--this
is why door knobs and marine components are typically
brasses--microbes/barnacles simply don't grow on them. Nickel is
also known to be anti-microbial, but is slightly more toxic than
copper. Essentially, higher copper and nickel content is preferred
for these anti-microbial/anti fouling type alloys.
High Formability Applications
[0091] Similar to regular brasses, with small additions of Al, Sn
and Zn these alloys only contain the soft and ductile `alpha` phase
in the annealed state. As more Al, Sn or Zn are added these alloys
begin to precipitate the much harder and less ductile `beta` phase.
When Al<4 at. % or Sn<4 at. % or Zn<30 at. % there is no
beta phase present and these alloys are lower strength, but highly
ductile. These alloys would be best suited to forming applications,
similar to say munitions brasses (spinning/forming of bullet
cartridges) or musical instruments or tubing where the metal is
drawn and formed extensively.
High Wear Resistance and Low Friction Applications
[0092] When 5<Al<20 or 4<Sn<10 or 30<Zn<40 (at.
%), these alloys exhibit a duplex microstructure, which is
considerably stronger and harder than alpha phase only alloys, but
still quite tough. These alloys would be best suited to the high
wear/low friction applications such as keys, hinges, gears/cogs,
zippers, door latches. With higher Zn and Al additions, these
alloys are also slightly lighter (lower density) and considerably
cheaper to produce than regular brasses.
Light Weight
[0093] The HEB alloys would not necessarily be considered as `light
weight` when compared with titanium or aluminium alloys for weight
savings alone. However, they are always `lighter` than typical
brasses (which are quite heavy) simply due to the presence of Mn
and Ni (which is still an advantage). The densities of HEB are
still generally comparable to steel.
[0094] However, for items that require specific strengths to
function with dimensions that can be altered based on this
requirement, further materials savings can be made. Specifically,
the HEBs exhibit strengths 10-30% higher than that of brasses or
bronzes with similar copper-to-zinc or copper-to-aluminium contents
and, therefore, less material is required to give the same product
strength. It follows that total materials cost savings from 19 to
47% are realistic for a given application.
Low Temperature Fracture Toughness
[0095] Traditional steel bolts are bcc and bcc microstructures
exhibit a temperature dependent ductile to brittle transition. It
is for this reason that cooling steel/bcc metals to a low
temperature can result in them shattering or cracking easily under
load. With Al<4 at % or Sn<4 at % or Zn<30 at. % these
alloys are fcc, hence do not display this ductile to brittle
behaviour at low temperatures. Even with a small amount of the bcc
phase, these alloys are expected to be ductile at low
temperatures.
Non-Sparking
[0096] Steel, stainless steel, titanium and magnesium all give off
sparks when ground with abrasives. This is not suitable for some
environments, particularly where volatiles/flammables are present.
Similar to regular brasses and bronzes, the HEB alloys do not spark
when ground.
Non-Marking/Staining (Fingerprints)
[0097] When polished, the HEB alloys seem to not stain or
fingerprint in the same way stainless steel does (for example,
brushed metal finish fridges and household appliances are quite
prone to permanent staining due to reactions with iron). This is
likely due to the oxidising potential of copper (metallic copper is
more stable). An HEB with higher Cu, Ni content and containing Al
(e.g. [Cu,Mn,Ni].sub.85-99Al.sub.1-15) is less susceptible to
marking in the same ways as stainless steel.
Magnetism
[0098] Some of these alloys exhibit strong ferromagnetic
properties. This is due to the presence of Mn in combination with
Al, Sn or Si in a magnetically ordered bcc phase. As Al, Sn and Si
content increases the volume fraction of the magnetic phase
increases, and so does the magnetic strength of the alloys. The
composition range is quite specific. For quaternary alloys, the
ranges are: [Cu,Mn,Ni].sub.70-80Al.sub.20-30,
[Cu,Mn,Ni].sub.70-95Sn.sub.5-30,
[Cu,Mn,Ni].sub.70-97.5Si.sub.2.5-30. Based on this ordered bcc
phase, the optimum quantity of Mn and (Al or Sn) is 25 at. %, e.g.
[Cu,Ni].sub.50Mn.sub.25[Al or Sn].sub.25. The optimum range for Si
is 15-25 at. %, e.g. [Cu,Ni].sub.50-60Mn.sub.25Si.sub.15-25. These
alloys are quite brittle and conventional powder consolidation
methods would be required to create permanent magnets.
[0099] Tin containing alloys show the highest magnetic response.
Zinc quaternary alloys are non-magnetic. Also, quinary alloys show
magnetism. Any combination of Sn and Al within this composition
range, e.g. [Cu,Mn,Ni].sub.70-95[Al,Sn].sub.5-30, will be magnetic.
Quinary alloys of Cu, Ni and Mn and including Zn and Al show faint
magnetism. However, quinary alloys of Cu, Ni and Mn and including
Zn and Sn exhibit moderate magnetism. This is due to Sn causing
strongly magnetic behaviour in alloys with relatively small amounts
of Sn, e.g. more than 5 at. %. For the same reason, it is expected
that alloys of Cu, Mn, Ni, Al, Zn and Sn will be magnetic due to
the presence of an ordered bcc phase.
Processing and Machinability
[0100] The HEB alloys may be processed in the same way as current
brasses with no modification to existing processing technology,
with similar melting and casting properties to conventional brasses
and similar post production working/machining properties.
[0101] Specifically, the addition of small amounts of Pb will
improve machinability. It is understood that Pb is immiscible with
regular brass and, therefore, forms a fine dispersion within the
brass which improves machinability of the bulk brass. It is
expected that similar additions of Pb in the HEBs will have a
similar effect.
[0102] This includes processes for application of coatings. To be
more specific, many brass-based products are plated with harder,
more corrosion resistant or more aesthetically pleasing coatings
such as chrome, nickel, silver or even gold. The electrochemical
properties allowing easy plating for these new high entropy brasses
remains unchanged compared to traditional brasses, hence these
commercial treatments are still completely compatible.
[0103] Recyclability
[0104] There already exists a world-wide brass recycling industry
and due to the corrosion resistance and relatively lower melting
point of brass--this is more economically viable and efficient than
recycling steels. These HEB alloys are no exception, and in-fact
could be reliably manufactured in-part by recycled traditional
brasses, reducing cost further per recycling iteration.
[0105] In the claims which follow, and in the preceding
description, except where the context requires otherwise due to
express language or necessary implication, the word "comprise" and
variations such as "comprises" or "comprising" are used in an
inclusive sense, i.e. to specify the presence of the stated
features but not to preclude the presence or addition of further
features in various embodiments of the apparatus and method as
disclosed herein.
* * * * *