CA1096756A - High strength copper base alloy and preparation thereof - Google Patents
High strength copper base alloy and preparation thereofInfo
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- CA1096756A CA1096756A CA270,907A CA270907A CA1096756A CA 1096756 A CA1096756 A CA 1096756A CA 270907 A CA270907 A CA 270907A CA 1096756 A CA1096756 A CA 1096756A
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22F—CHANGING THE PHYSICAL STRUCTURE OF NON-FERROUS METALS AND NON-FERROUS ALLOYS
- C22F1/00—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working
- C22F1/08—Changing the physical structure of non-ferrous metals or alloys by heat treatment or by hot or cold working of copper or alloys based thereon
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Abstract
ABSTRACT OF THE DISCLOSURE
Spinodal, precipitation hardened copper base alloy is prepared having high strength and favorable strength to ductility characteristics. The alloy consists essentially of from 10 to 30% nickel, 1 to 5% aluminum and the balance essentially copper. The microstructure of the alloy is characterized by including finely dispersed precipitates of Ni3Al particles dispersed throughout the alloy matrix. This alloy is particularly useful for electrical contact springs.
Spinodal, precipitation hardened copper base alloy is prepared having high strength and favorable strength to ductility characteristics. The alloy consists essentially of from 10 to 30% nickel, 1 to 5% aluminum and the balance essentially copper. The microstructure of the alloy is characterized by including finely dispersed precipitates of Ni3Al particles dispersed throughout the alloy matrix. This alloy is particularly useful for electrical contact springs.
Description
BACKGROUND O~ THE INVENTION
It is highly desirable to provide copper base alloys havlng high strength properties and favorable strength to ductility characteristics. It is particularly desirable to provide low cost hot and cold workable copper base alloys which are characterized by high mechanical strength, favorable strength to ductility combinations and excellent formability characterlstics. It is especially desirable to provide copper base alloys characterized as aforesaid which are convenient to process and which may be made economically on a commercial scale.
It is highly desirable to provide alloys of the fore-going type which satisfy the stringent requirements imposed by modern applications for electrical contact springs in which high strength is requlred coupled wlth good bend formability as well as reslstance to mechanical property degradation at moderately elevated temperatures, such as stress relaxation resistance.
Commerclally, copper alloys tend to be deficient ln one or more of the foregolng characteristics. For example, the commercial copper Alloy 510 (a phosphor-bronze containing from 3.5 to 5.8% tin and from 0.03 to 0.35% phosphorus) is superior ln strength but poor ln bend characterlstlcs. The commerclal copper Alloy 725 (a copper-nickel contalnlng 8.5 to 10.5% nickel and 1.8 to 2.8% tin) is superlor with respect to bend properties, solderabllity and contact resistance, but deflcient in strength.
The present lnvention relates to spincdal, preclpitation hardened copper base alloys and the preparation therecf, sald alloys having an unusual combination of properties based on a Ji~
lQ~6756 composition containing ~rom 10 to 30% nickel and from 1 to 5%
alumlnum. Nickel-aluminum containing copper base alloys are known in the art, such as disclosed in U.S. Patents 2,101,087,
It is highly desirable to provide copper base alloys havlng high strength properties and favorable strength to ductility characteristics. It is particularly desirable to provide low cost hot and cold workable copper base alloys which are characterized by high mechanical strength, favorable strength to ductility combinations and excellent formability characterlstics. It is especially desirable to provide copper base alloys characterized as aforesaid which are convenient to process and which may be made economically on a commercial scale.
It is highly desirable to provide alloys of the fore-going type which satisfy the stringent requirements imposed by modern applications for electrical contact springs in which high strength is requlred coupled wlth good bend formability as well as reslstance to mechanical property degradation at moderately elevated temperatures, such as stress relaxation resistance.
Commerclally, copper alloys tend to be deficient ln one or more of the foregolng characteristics. For example, the commercial copper Alloy 510 (a phosphor-bronze containing from 3.5 to 5.8% tin and from 0.03 to 0.35% phosphorus) is superior ln strength but poor ln bend characterlstlcs. The commerclal copper Alloy 725 (a copper-nickel contalnlng 8.5 to 10.5% nickel and 1.8 to 2.8% tin) is superlor with respect to bend properties, solderabllity and contact resistance, but deflcient in strength.
The present lnvention relates to spincdal, preclpitation hardened copper base alloys and the preparation therecf, sald alloys having an unusual combination of properties based on a Ji~
lQ~6756 composition containing ~rom 10 to 30% nickel and from 1 to 5%
alumlnum. Nickel-aluminum containing copper base alloys are known in the art, such as disclosed in U.S. Patents 2,101,087,
2,101,626 and 3,399,057; however, these teachings do not contemplate spinodal, precipitation hardened copper alloys having finely dispersed precipitates of Ni3Al particles as disclosed in the present invention.
Accordingly, it is a principal ob~ect of the present invention to provide improved copper base alloys having high strength and favorable strength to ductility characteristics and a method for the preparation thereof.
It is a further ob~ect of the present invention to provide an improved copper base alloy as aforesaid which has other good properties, such as e~cellent formability character-istics in the precipitation hardened condition and resistance to mechanical property degradation at moderately elevated temperatures, such as stress rela~ation resistance, which alloy is particularly useful for electrical contact sprlngs.
It ls a -still further ob~ect of the present inventlon to provide an lmproved copper base alloy as aforesaid which is convenient to process and whlch may be made economlcally on a commerclal scale.
Further ob~ects and advantages of the present lnvention wlll appear herelnbelow.
SUMMARY OF THE INVENTION
In accordance wlth the present invention it has been found that the foregolng ob~ects and advantages may be readily achleved. The present invention resides in a spinodal, precipitatlon hardened copper base alloy having high strength and favorable strength to ductility character-1~'a6756 istics consistlng essentially of from 10 to 30~ nlckel, 1 to 5% aluminum, and the balance essentially copper, wherein the matrix of the alloy is characterized by including finely dispersed precipitates of Ni3Al particles dispersed through-out the alloy matri~.
The nickel and aluminum contents provide the precipi-tation hardening mechanism through the precipitation of the Ni3Al type phase from a solution treated and cooled or solution treated, cooled and cold worked m~tri~. The morphology o~ the precipitate is controlled through appro-priate choice of processing and/or alloying schemes. The control of the finely dispersed precipitate morphology in turn controls the strength to ductility combination o~fered by the remarkable alloy system of the present invention.
By the present invention there is provided a method for obtaining a spinodal, precipitation hardened copper base alloy having high strength and favorable strength to ductility characteristics which comprises: (A) providing a copper base alloy consisting essentially of:(l) 10 to 30% by weight nickel;
(2) from 1 to 5% by weight aluminum; (3) from 0% to 20% by weight of an element selected from the group consisting of zinc, iron, tin, titanium, zirconium, hafnium, beryllium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, and mixtures thereof; (4) from 0% to 5% by weight of an element selected from the group consisting of lead, arsenic, antimony, boron, phosphorus, manganese, silicon, a lanthanide metal, magnesium, lithium, and mixtures thereof; and (5) the balance being copper; (B) hot working said alloy with a finishing temperature in excess of 400C; (C) solution annealing said alloy for from 10 seconds to 24 hours at a temperature of lQ~6756 from 650 to 1100C; and (D) cooling the alloy to room temperature; thereby to provide a spinodal, precipitation hardened copper base alloy wherein the microstructure is characterized by the presence of finely dispersed precipitates of Ni3Al particles dispersed throughout the matrix.
The process of the present invention is surprisingly versatile and a great many variations may be employed to provide a wide variety o~ property combinations. A homogeni-zation treatment may be employed prior to hot rolling, or as part of the hot rolling operation. The alloy may b~ cold worked (preferably rolled) with or without intermediate -3a-anneals after hot rolling and prior to solution annealing.
Processing following the solution anneal is particu-larly important in obtaining property variations. Thus, one may water quench from solution anneal followed by aging or cold rolling and aging. Alternatively, one may cool slowly to ambient temperature and use the alloy in that conditlon, or age, or cold roll and age, or cool slowly dlrectly to aging temperature followed by cooling to ambient temperature.
The preferred working operation is rolling and will be discussed as such throughout the present specification;
however, any working operation may be used, such as extrusion, forging or wire drawing.
Thus, the alloys of the present invention will be processed to provide finely dispersed Ni3Al type precipi-tates of three morphologies depending upon desired mechanical properties and/or processing characteristics. Firstly, the finely dispersed N13Al type precipltates may be formed as large agglomerated grain boundary particles or scattered spheroldal dlspersoid particles provlded by the mechanism of classical nuoleatlon and growth of second phase particles at the graln boundaries or lattice defects. A second type of flnely dlspersed preclpltate is characterized by the N13Al type preclpltates formed in a finely dlspersed manner by separatlng from the alpha copper constituent by the mechanism of dlscontlnuous precipitation. A third type of finely dispersed Ni3Al precipitate is characterized by a precipi-tate being formed as an array of extremely finely dispersed, coherent particles.
The foregoing finely dispersed precipitates find their origin in a spinodal decomposition of the supersaturated ~q6756 solid solution followed by coarsening and transformation of the solute rich regions into Ni3Al pre-precipitates and equilibrium precipitate particles. The spinodal decomposi-tion mechanism provides for the unusual strength to ductility combinations which are achieved by the alloy system of the present invention. This is particularly surprising since other spinodal type alloys do not exhibit this unusually good strength to bend ductility in the aged condition, e.g., the copper-nickel-tin system does not exhibit these properties.
DETAILED DESCRIPTION
As indicated hereinabove, the present invention resides in a family of hot and cold rollable, spinodal, precipitation hardened copper base alloys containing nickel and aluminum and the preparation thereof. The alloys of the present invention are characterized by a combination of excellent properties includlng high mechanical strength, favorable strength to ductility combinations, excellent formability in the precipitation hardened condition, and resistance to mechanical property degradation at moderately elevated temperatures, such as stress relaxation resistance.
Throughout the present specification, percentages of materials refers to weight percentages.
The nickel content in the alloy of the present invention will vary from 10 to 30% and is preferably maintained in the range of from 10 to 20%. The aluminum content will vary from 1 to 5% and is preferably maintained in the range of 1.5 to 3.5~.
3o Other alloying lngredients may be included in the alloy of the present invention in order to obtain particular comblnations of properties. Thus, a total of up to 20% of one or more of the following materials may be included:
Titanium, zirconium, hafnium, beryllium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, zinc, iron and tin.
The zinc, iron and tin components may be used in an amount from 0.01 to 10% each and are employed to provide additional solution strengthening, work hardening and precipitation hardening since they partition eaually or preferentially to the nickel-aluminum rich precipitate and to the alpha copper matrix, thereby making the matrix and precipitate harder by affecting the lattice par2meters of the matrix and the precipitate so as to increase the interfacial coherency strains and to provide for enhanced precipitation hardening.
In addition, the iron in solution restricts grain growth.
The titanium, zirconium, hafnium and beryll um components may be employed in an amount .rom 0.01 to 5~ each. These materials provide for a second precipitate particle ir. the alloy matrix by forming intermediate phases t~ith copper and/or nickel. The vanadium, niobium, tantalum, chromium, molybdenum and tungst~n components may also be employed in an amount from 0.01 to 5~ each. These components are desirable since they provide for second precipitate particles in the alloy matrix in their own elemental form. Therefore, ~he titanium, 2irconium, hafnium, beryllium, vanadium, niobium, tantalum, chromium and molybdenum or tungsten or mixtures of these may readily be utilized in the alloy system of the present invention in order to provide additional particle hardening, with the alloy matrix including second precipit2te particles l~a6756 containlng said materials, or to provide improved processing characteristics, such as providing for grain size control.
Moreover, even small amounts of each of the foregoing elements are capable of influencing the reaction kinetics and morphology hardness of the base Ni3Al precipitation process.
In addition to the foregoing, a total of up to 5% of one or more of the following materials may be present in an amount from 0.001 to 3% each: Lead, arsenic, antimony, boron, phosphorus, manganese, silicon, a lanthanide metal, such as mischmetal or cerium, magnesium and/or lithium. These materials are useful in improving mech~nical propertles or corrosion resistance or processing. ~he alloy melt may oe deoxidized ~ith such additions as are traditionally used to deo~idize or desulphurize copper, such as manganese, lithium, silicon, boron, magnesium or misch~etal. In fact, even those ele~.ents listed above as solution or precipitation or dispersed additives may be used in small amounts to deoxidize the melt, such as titanium, zirconium, hafnium, chromium, molybdenum and e~cess aluminum.
Naturally, 2.rsenic and antimony additions may be used to promote corrosion resistance. '~Ioreover, compositions containing lead, sulfur and/or tellurium additlons ~ould provide the additional benefits of a highly machinable alloy, provided, however, that these alloys would not be readily hot rollable.
As discussed hereinabove, the nic~el and aluminum components of the alloy of the present invention provide the precipitation hardening mechanism through the spir.odal precipitation of the Ni3Al type phase from a solution treated and cooled, or solution treated cooled and cold rolled matrix.
1(~967~6 Appropriate choice of processing and~or alloy schemes may be used to control the morphology of the precipitate and in turn controls the strength to ductility combinations ln the alloy system of the present invention.
Hence, as indicated hereinabove, a key feature of the alloy of the present invention is the presence of finely dlspersed precipitates of Ni3Al particles which are dispersed throughout the alloy matrix. The alloys may be processed to provide Ni3Al type precipitates of three morphologies depending upon desired mechanical properties and~or proc-essing characteristics. A first of these morphologies, type ~1), is characterized by finely dispersed Ni3Al type precipitates formed as agglomerated grain boundary particles, or scattered spheroidal disperscids provided by the mechanism of classical nucleation and gro-.~th of second phase particles at grain boundaries or at lattice defects. A second, type (2), of finely dispersed Ni3Al type precipitates may be formed in a finely dispersed manner by separating from the alpha copper constituent by the mechanism of discontinuous precipitatlon. A third, type (3), of finely dispersed precipitates of Ni3Al type precipitate may be formed as an array of extremely finely dispersed, coherent particles.
The foregoin~ inely dispersed precipitates of Ni3Al particles dispersed throughout the alloy ~.atrix ~ind their origin in a spinodal decomposition of the supersaturated solid solution followed by coarsening and trans~ormation of the solute rich reg~ons into Ni3Al pre-orecipitates and equilibrium precipitate particles. These particles are formed by a soinodal decomposition mechanism that provides for the unusual properties obtained in accordance -~ith the 7001-M~
lQ~6756 present invention.
The alloy of the present invention may be cast in any convenient manner such as direct chill or continuous casting.
The alloy should be homogenized at temperatures between 600C
and the solidus temperature of the particular alloy for at least 15 minutes followed by hot rolling with a finishing temperature in excess of 400C. For example, a representative alloy composition containing 15% nickel and 2~o aluminum of the present invention has a solidus temperature of 1120C. The homogenizing procedure may be combined with the hot rolling procedure, that is, the alloy may be heated to hot rolling starting temperature and held at said starting temperature or the requisite period of time. The hct rolling starting temperature should preerably be in the solid solution range appropriate to the particular composition.
Followlng hot rollir.g, the alloy may be cold rolled at a temperature below 200C ~lith or ~ithout intermediate annealing depending upon particular gage requirements. In general, annealing may be performed using strip or batch processing with holding times of from 10 seconds to 24 hours at temperatures from 250C to wlthin ,0C o. the solidus temperature for the particular alloy.
The alloy should then be given a solution treatment within the temperature range of 650C to 1100C, and generally above 800C. This is a key step ir. the processing of the present invention since this step is reauired for the formation on cooling of the e~tremely finely dispersed ~i3Al particles by 2 spinodal decompositJon mechanism. The solution annealing ste~ should be carried out or from 10 seconds to 24 hours.
_9_ lQq~75~
Following solution annealing, the material should be cooled to room temperature. In accordance with the present lnvention it has been found that critical control of proc-essing parameters can result in significantly different property combir~tions. In particular, it has been found that the cooling rate from the solution treatment temperature is important in controlling the morphology of the precipitation product upon subsequent aging of solution tre2ted or solution treated and cold rolled material. When the alloys are water quenched from solution treatment, for example, cooled at average rates of 650C per minute or faster, one observes the dlscontinuous type (2) and possibly also the agglomerated type (1~ of Ni3Al precipitate in the aged product. ~aterial ;
which is water quenched from solution tre2~ment followed by cold rolllng and aging results in 2 mixture of all three r types of Mi3Al precipitates. When the alloys are slowly cooled from solution treatment, or example, at average rates of 80C per minute cr less, one observes type (3) of Ni3Al type precipitate formed as an array of extremely finely dispersed, ccherent particles. This is observed in the solution treated product per se or in the solution treated and aged product or in the solution tre~ted cold rolled and aged product. Alternatively, one may simply cool the solution annealed product directly to aging tem~erature, age at the aging temperature followed by cooling to room temperature, resulting in the foregoing type of precipitate (3).
Thus, ollowing solution annealing one may cool the material using 2 slow cooling mechanism or quenching mechanlsm as indicated hereinabove. In addition, one may age 3o the solution treated material at a temperature o from 250C
~Q~S7~
to 650C for times of from 30 mlnutes to 24 hours. The final condition of the materlal may be either solutlon treated, solutlon treated and aged, or solution treated, cold rolled and aged.
Alternatlvely, one may provide additional cold rolling after the aging treatment. This additional cold rolling results in additional strength but loss in formability and ductility.
For applications where maximum ductility is desired the alloy should be quenched after the solution anneal. Subse-quent cold rolling and aging generates both higher strength and better ductility thar. the as cold rolled metal. This improvement in both of these properties with aging is quite remarkable.
If maximum strength is desired rather than maximum ductility, the alloys should be slowly cooled from the solution anneal. Subsequent processing of this condition, including cold rolling and aging, results in increased strength with only slight loss in formability. It is quite surpris~ng that material slowly cooled from solution anneal-ing in this manner e~hibits an aging response. Thus, the alloys of the present invention may be processed to obtain a variety of properties related to con~rol of the cooling rate following the solution anneal at a temperature of from 650C
to 1100C. The aging step at tempera~ures of from 250C to 650C fcr times of from 3G minutes to 24 hours results in improved property combinations. The alloys may optionaliy be cold rolled, for example, up to 90~, between the solution anneal ard ~he aging steps, if desired, with the particular variations and the degree of rollirg depending upon the final 1(Pa\~756 property requirements.
Parts may be formed from cold rolled and/or aged materlal, with an optional heat treatment after forming. The heat treatment may be an aging treatment as above, or a low temper-ature thermal treatment at 150 - 300C for at least 15 minutes to enhance stress relaxation or stress corrosion resistance.
The present invention and i~.provements resulting therefrom will be more readily understandable from a consideration of the following illustrative examples. ~
EXAMPLE I - Tensile properties An alloy consisting of 15 wt. ,0 nickel and 2 wt. ~
aluminum, balance cop~er was cast from 1350C into a steel mold with a water-cooled copper base plate. The ten pound ingot was soaked at 1000C for four hours, immedlately hot rolled to 0.4" from 1.75" with a finishing temperatùre of about 500C and cold rolled to 0.120". The alloy was solution treated at 850C for one hour followed by water quenching to room te~.perature. The alloy was further processed to prov de metal at 0.020" gauge in the as-quenched and 20, 40, 60 and 83% cold rolled condltlon. Some metal was cold rolled directly to 0.020", that is, 83~ cold rolled metal. Some metal was cold rolled to 0.050" gauge again solution treated one hour at 850C and cold rolled to Q.020" gauge, i.e., 60%
cold rolled metal. Some metal was cold rolled to 0.033"
gauge, solution treated one hour at 850C and cold rolled to 0.020" gauge, i.e., 40~ cold rolled metal. Some metal was cold rolled to 0.025" gauge solution treated one hour at 850C and cold rolled to 0.020" gauge, i.e., 20% cold rolled metal. Some of the 60% cold rolled metal was solution treated at 850C/l hr. to provide solution treated metal, ~61 56 i.e., 0% reduction. After every solution treatment the metal was water quenched to room temperature. Some of each of the cold rolled metal at 0.020" was heat treated taged) at 400C
for 24 hours. Tensile propertles were measured for both the as-cold rolled and heat treated material. These tensile properties are listed in Table I. These properties are compared with those of the commercial high strength copper base alloys CDA 510 (4.4% tin, 0.07% phosphorus, balance copper) and CDA 638 ~2.7% aluminum, 1.7% silicon, 0.4% cobalt, balance copper). The data in Table I clearly demonstrate the significant heat treated strength and strength/ductility combination advantages obtained in accordance wit~ the alloy of the present invention. The microstructures of the aged materials of the present invention were examined and found to contain finely dispersed precipitates of Ni3Al particles dispersed throughout the matrix.
1~6756 Table I
Tensile Properties of Cu-15Ni-2Al Water ~uenched from the Solution Treatment Alloy % Cold 0.2~ Yield ~e ile Elongation Reduction StrenOt)h _ ns (%) Cu-15Ni-2A1 0 22 60 32.8 Cu-15Ni-2AlO+Aged 76 113 17.2 CDA 510 0 40 56 46.0 CDA 638 0 51 80 35.0 Cu-15Ni-2A1 20 59 66 13.3 Cu-15Ni-2A120+Aged 81 115 17.7 CDA 510 20 65 72 20.0 CDA 638 20 82 106 10.0 Cu-15Ni-2A1 40 78 81 1.0 Cu-15Ni-2A140~Aged 91 120 16.8 CDA 510 40 93 97 5.0 CDA 638 40 99 120 5.0 Cu-15Ni-2A1 60 84 86 1.3 Cu-15Ni-2A16~Aged 105 125 15.0 C3A 510 60 107 110 2.0 CDA 638 60 110 130 3.0 Cu-15Ni-2A1 83 90 92 1.0 Cu-15Ni-2A183+.~ed 118 141 14.0 CDA 510 83 114 120 1.0 CDA 638 83 118 139 1.0 - EXAMPLE II - ~ensile Properties An alloy consisting of 15 wt. ~c nicXel and 2 wt. ~
aluminum was cast and processed as described in E~ample I, except that the metal was air cooled to room temperature following each solution treatment. Again, the tensile properties were measured for both the as-cold rolled and heat treated (aged) condition. The microstructures of the solutior.
treated, solution treated and cold rolled, and solution treated, cold rolled and aged condl'ions o. the alloys of the present invention were exa~.ir.ed and found to contain finely dispersed precipitates of Ni3Al particles dispersed through-out the ~atrix. Compared with the propertles OL the two commercial high strength Allo~s 510 and 638 in Table I, the lQ467S6 data in Table II clearly demonstrates the significant rolled temper strength advantage as well as the heat treated strength advantages obtained in accordance with processing the alloy of the present invention in this way. It is particularly surprising that slowly cooled, heat treatable alloys can be cold rolled to such an extent as in this example without breaking up.
Table II
Tensile Properties of Cu-15Ni-2A1 Air-Cooled from the Solution Treatment Condition 0.2~ Yield UltimateElongation Strength Tensile (~) (ksi) Strength (ksi) Solution treated46 88 28.G
S.T. + Aged 52 92 19.7 CR 20do 128 133 4.8 CR 20% + Aged 132 137 2.9 CR 40% 132 142 1.0 CR 40~ + Aged 144 154 2.1 CR 60~ 131 142 2.0 CR 60% + Aged 148 158 2.1 CR 83d 125 139 3.5 CR 83~ + Aged 151 170 3.0 E~AMPLE III - Ber.d Formability Properties The bend for~ability of the Cu-15Ni-2Al alloy, processed as in Examples I and II, was evaluated. In particular, the 90 bend property for the heat treated (aged) condition was measured. The bend properties determine the minimum radius about which strip can be bent without crackir.g. ~nere the bend is made about ar. axis either perpendicular to or parallel 75~;
to the rolling direction, the longitudinal properties (goodway) refer to the axis perpendicular to the rolling directlon, while the transverse properties (badway) refer to the axis parallel to the rolling direction. MBR is the smallest radius which does not show cracks and t is the thickness of the strip, i.e., all at 0.020" gauge in this case. The resulting bend data are presented in Tables IIIA, IIIB, IIIC and IIID. Tables IIIA and IIIB compare the bend properties of Cu-15Ni-2Al that had been processed with water quenching and air cooling, respectively. Table IIIC compares the M~R/t available for Alloys 510 and 638 with the MBR/t for an alloy of the present invention. Surpr~singly, for a giver strength level, the heat treated alloy of the present invention offers greater bend fcrmability, either goodway or badway, i.e., lower MBR/t, thar do Alloys 510 and 638. Table IIID is a similar comparison showing the higher yield strength available at a given MBR/t for the alloys of this invention compared to Alloys 510 and 638. It is co~.ercially desirable to obtain higher strength for a given bend radius and the heat treated Cu-15Ni-2Al alloy offers greater strength for a given bend radius, especially in the critical badway mode, than the high strength commercial wrought Alloys 510 and 638. It is particularly significant that the alloy of the present invention has adequate bend ductility at strength levels the other alloys cannot attain.
3o Table IIIA
Bend Properties of Cold Rolled And Aged Cu-15Ni-2Al, That Had Been Water Quenched From The Solution Treatment Temperature Minimum Bend Radius / thickness Condition* Aged 0.2% YS, Cu-15Ni-2Al ksi G.W. B.W.
Quenched + Aged76 sharp sharp - 10 CR 20% + Aged 81 0 . 4 1. 6 CR 40% + Aged 91 0. 4 0 . 4 CR 60% + Aged105 0. 8 1. 6 CR 83~o + Aged118 7.8 9.4 * Aged 400C-24 hrs. at 0.020" gauge Table IIIB
Bend Properties o~ Cold Rolled And Aged Cu-15Ni-2Al, That Had Been Air Cooled From The Solution Treatment Tem~erature -Minlmum Bend Radius / thicXness Condition* Aged 0.2~ YS, Cu-15~i-2Al ksi G.W. B.W.
Cooled + Aged 52 sharp sharp CR 20~ + Aged132 6.2 5.5 CR 40~ + Aged144 6.2 5.5 CR 60~ + Aged148 6.2 7.8 CR 83~ + Aged151 7.8 12.5 * .4ged 400C-24 hrs. at Q.020" gauge 6~S6 Table IIIC
Comparison of Bend Properties of Cold Rolled And Aged Cu-15Ni-2Al With Those of Temper Rolled CDA 510 And 638 Minimum Bend Radius / thickness 0.2~ Yield Cu-15Ni-2A1 510 638 Strength, ksi G _ B.W. G.W. B.W. G.W. B.W._ 0.2 0.2 0.2 1.6 0.8 2.1 0.4 0.4 0.4 3.2 1.5 3.3 100 0.7 1.1 1.0 4.3 2.2 4.3 110 1.4 2.0 1.8 9.0 3.2 10.0 120 2.4 3.2 _ _ 4.8 >25 130 4.2 5.0 - - - -140 5.7 7.0 Table IIID
Comparison o~ Strength/Ber.d Property Combinations of Cold Rolled And Aged Cu-l~N~-2Al With Those of ~emper Rolled C~A 510 And CDA 638 0.2% Yield St~ength, ksi Goodway Aged Cold RolledCold Rolled MBRf~ Cu-15Ni-2A1 510 638
Accordingly, it is a principal ob~ect of the present invention to provide improved copper base alloys having high strength and favorable strength to ductility characteristics and a method for the preparation thereof.
It is a further ob~ect of the present invention to provide an improved copper base alloy as aforesaid which has other good properties, such as e~cellent formability character-istics in the precipitation hardened condition and resistance to mechanical property degradation at moderately elevated temperatures, such as stress rela~ation resistance, which alloy is particularly useful for electrical contact sprlngs.
It ls a -still further ob~ect of the present inventlon to provide an lmproved copper base alloy as aforesaid which is convenient to process and whlch may be made economlcally on a commerclal scale.
Further ob~ects and advantages of the present lnvention wlll appear herelnbelow.
SUMMARY OF THE INVENTION
In accordance wlth the present invention it has been found that the foregolng ob~ects and advantages may be readily achleved. The present invention resides in a spinodal, precipitatlon hardened copper base alloy having high strength and favorable strength to ductility character-1~'a6756 istics consistlng essentially of from 10 to 30~ nlckel, 1 to 5% aluminum, and the balance essentially copper, wherein the matrix of the alloy is characterized by including finely dispersed precipitates of Ni3Al particles dispersed through-out the alloy matri~.
The nickel and aluminum contents provide the precipi-tation hardening mechanism through the precipitation of the Ni3Al type phase from a solution treated and cooled or solution treated, cooled and cold worked m~tri~. The morphology o~ the precipitate is controlled through appro-priate choice of processing and/or alloying schemes. The control of the finely dispersed precipitate morphology in turn controls the strength to ductility combination o~fered by the remarkable alloy system of the present invention.
By the present invention there is provided a method for obtaining a spinodal, precipitation hardened copper base alloy having high strength and favorable strength to ductility characteristics which comprises: (A) providing a copper base alloy consisting essentially of:(l) 10 to 30% by weight nickel;
(2) from 1 to 5% by weight aluminum; (3) from 0% to 20% by weight of an element selected from the group consisting of zinc, iron, tin, titanium, zirconium, hafnium, beryllium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, and mixtures thereof; (4) from 0% to 5% by weight of an element selected from the group consisting of lead, arsenic, antimony, boron, phosphorus, manganese, silicon, a lanthanide metal, magnesium, lithium, and mixtures thereof; and (5) the balance being copper; (B) hot working said alloy with a finishing temperature in excess of 400C; (C) solution annealing said alloy for from 10 seconds to 24 hours at a temperature of lQ~6756 from 650 to 1100C; and (D) cooling the alloy to room temperature; thereby to provide a spinodal, precipitation hardened copper base alloy wherein the microstructure is characterized by the presence of finely dispersed precipitates of Ni3Al particles dispersed throughout the matrix.
The process of the present invention is surprisingly versatile and a great many variations may be employed to provide a wide variety o~ property combinations. A homogeni-zation treatment may be employed prior to hot rolling, or as part of the hot rolling operation. The alloy may b~ cold worked (preferably rolled) with or without intermediate -3a-anneals after hot rolling and prior to solution annealing.
Processing following the solution anneal is particu-larly important in obtaining property variations. Thus, one may water quench from solution anneal followed by aging or cold rolling and aging. Alternatively, one may cool slowly to ambient temperature and use the alloy in that conditlon, or age, or cold roll and age, or cool slowly dlrectly to aging temperature followed by cooling to ambient temperature.
The preferred working operation is rolling and will be discussed as such throughout the present specification;
however, any working operation may be used, such as extrusion, forging or wire drawing.
Thus, the alloys of the present invention will be processed to provide finely dispersed Ni3Al type precipi-tates of three morphologies depending upon desired mechanical properties and/or processing characteristics. Firstly, the finely dispersed N13Al type precipltates may be formed as large agglomerated grain boundary particles or scattered spheroldal dlspersoid particles provlded by the mechanism of classical nuoleatlon and growth of second phase particles at the graln boundaries or lattice defects. A second type of flnely dlspersed preclpltate is characterized by the N13Al type preclpltates formed in a finely dlspersed manner by separatlng from the alpha copper constituent by the mechanism of dlscontlnuous precipitation. A third type of finely dispersed Ni3Al precipitate is characterized by a precipi-tate being formed as an array of extremely finely dispersed, coherent particles.
The foregoing finely dispersed precipitates find their origin in a spinodal decomposition of the supersaturated ~q6756 solid solution followed by coarsening and transformation of the solute rich regions into Ni3Al pre-precipitates and equilibrium precipitate particles. The spinodal decomposi-tion mechanism provides for the unusual strength to ductility combinations which are achieved by the alloy system of the present invention. This is particularly surprising since other spinodal type alloys do not exhibit this unusually good strength to bend ductility in the aged condition, e.g., the copper-nickel-tin system does not exhibit these properties.
DETAILED DESCRIPTION
As indicated hereinabove, the present invention resides in a family of hot and cold rollable, spinodal, precipitation hardened copper base alloys containing nickel and aluminum and the preparation thereof. The alloys of the present invention are characterized by a combination of excellent properties includlng high mechanical strength, favorable strength to ductility combinations, excellent formability in the precipitation hardened condition, and resistance to mechanical property degradation at moderately elevated temperatures, such as stress relaxation resistance.
Throughout the present specification, percentages of materials refers to weight percentages.
The nickel content in the alloy of the present invention will vary from 10 to 30% and is preferably maintained in the range of from 10 to 20%. The aluminum content will vary from 1 to 5% and is preferably maintained in the range of 1.5 to 3.5~.
3o Other alloying lngredients may be included in the alloy of the present invention in order to obtain particular comblnations of properties. Thus, a total of up to 20% of one or more of the following materials may be included:
Titanium, zirconium, hafnium, beryllium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, zinc, iron and tin.
The zinc, iron and tin components may be used in an amount from 0.01 to 10% each and are employed to provide additional solution strengthening, work hardening and precipitation hardening since they partition eaually or preferentially to the nickel-aluminum rich precipitate and to the alpha copper matrix, thereby making the matrix and precipitate harder by affecting the lattice par2meters of the matrix and the precipitate so as to increase the interfacial coherency strains and to provide for enhanced precipitation hardening.
In addition, the iron in solution restricts grain growth.
The titanium, zirconium, hafnium and beryll um components may be employed in an amount .rom 0.01 to 5~ each. These materials provide for a second precipitate particle ir. the alloy matrix by forming intermediate phases t~ith copper and/or nickel. The vanadium, niobium, tantalum, chromium, molybdenum and tungst~n components may also be employed in an amount from 0.01 to 5~ each. These components are desirable since they provide for second precipitate particles in the alloy matrix in their own elemental form. Therefore, ~he titanium, 2irconium, hafnium, beryllium, vanadium, niobium, tantalum, chromium and molybdenum or tungsten or mixtures of these may readily be utilized in the alloy system of the present invention in order to provide additional particle hardening, with the alloy matrix including second precipit2te particles l~a6756 containlng said materials, or to provide improved processing characteristics, such as providing for grain size control.
Moreover, even small amounts of each of the foregoing elements are capable of influencing the reaction kinetics and morphology hardness of the base Ni3Al precipitation process.
In addition to the foregoing, a total of up to 5% of one or more of the following materials may be present in an amount from 0.001 to 3% each: Lead, arsenic, antimony, boron, phosphorus, manganese, silicon, a lanthanide metal, such as mischmetal or cerium, magnesium and/or lithium. These materials are useful in improving mech~nical propertles or corrosion resistance or processing. ~he alloy melt may oe deoxidized ~ith such additions as are traditionally used to deo~idize or desulphurize copper, such as manganese, lithium, silicon, boron, magnesium or misch~etal. In fact, even those ele~.ents listed above as solution or precipitation or dispersed additives may be used in small amounts to deoxidize the melt, such as titanium, zirconium, hafnium, chromium, molybdenum and e~cess aluminum.
Naturally, 2.rsenic and antimony additions may be used to promote corrosion resistance. '~Ioreover, compositions containing lead, sulfur and/or tellurium additlons ~ould provide the additional benefits of a highly machinable alloy, provided, however, that these alloys would not be readily hot rollable.
As discussed hereinabove, the nic~el and aluminum components of the alloy of the present invention provide the precipitation hardening mechanism through the spir.odal precipitation of the Ni3Al type phase from a solution treated and cooled, or solution treated cooled and cold rolled matrix.
1(~967~6 Appropriate choice of processing and~or alloy schemes may be used to control the morphology of the precipitate and in turn controls the strength to ductility combinations ln the alloy system of the present invention.
Hence, as indicated hereinabove, a key feature of the alloy of the present invention is the presence of finely dlspersed precipitates of Ni3Al particles which are dispersed throughout the alloy matrix. The alloys may be processed to provide Ni3Al type precipitates of three morphologies depending upon desired mechanical properties and~or proc-essing characteristics. A first of these morphologies, type ~1), is characterized by finely dispersed Ni3Al type precipitates formed as agglomerated grain boundary particles, or scattered spheroidal disperscids provided by the mechanism of classical nucleation and gro-.~th of second phase particles at grain boundaries or at lattice defects. A second, type (2), of finely dispersed Ni3Al type precipitates may be formed in a finely dispersed manner by separating from the alpha copper constituent by the mechanism of discontinuous precipitatlon. A third, type (3), of finely dispersed precipitates of Ni3Al type precipitate may be formed as an array of extremely finely dispersed, coherent particles.
The foregoin~ inely dispersed precipitates of Ni3Al particles dispersed throughout the alloy ~.atrix ~ind their origin in a spinodal decomposition of the supersaturated solid solution followed by coarsening and trans~ormation of the solute rich reg~ons into Ni3Al pre-orecipitates and equilibrium precipitate particles. These particles are formed by a soinodal decomposition mechanism that provides for the unusual properties obtained in accordance -~ith the 7001-M~
lQ~6756 present invention.
The alloy of the present invention may be cast in any convenient manner such as direct chill or continuous casting.
The alloy should be homogenized at temperatures between 600C
and the solidus temperature of the particular alloy for at least 15 minutes followed by hot rolling with a finishing temperature in excess of 400C. For example, a representative alloy composition containing 15% nickel and 2~o aluminum of the present invention has a solidus temperature of 1120C. The homogenizing procedure may be combined with the hot rolling procedure, that is, the alloy may be heated to hot rolling starting temperature and held at said starting temperature or the requisite period of time. The hct rolling starting temperature should preerably be in the solid solution range appropriate to the particular composition.
Followlng hot rollir.g, the alloy may be cold rolled at a temperature below 200C ~lith or ~ithout intermediate annealing depending upon particular gage requirements. In general, annealing may be performed using strip or batch processing with holding times of from 10 seconds to 24 hours at temperatures from 250C to wlthin ,0C o. the solidus temperature for the particular alloy.
The alloy should then be given a solution treatment within the temperature range of 650C to 1100C, and generally above 800C. This is a key step ir. the processing of the present invention since this step is reauired for the formation on cooling of the e~tremely finely dispersed ~i3Al particles by 2 spinodal decompositJon mechanism. The solution annealing ste~ should be carried out or from 10 seconds to 24 hours.
_9_ lQq~75~
Following solution annealing, the material should be cooled to room temperature. In accordance with the present lnvention it has been found that critical control of proc-essing parameters can result in significantly different property combir~tions. In particular, it has been found that the cooling rate from the solution treatment temperature is important in controlling the morphology of the precipitation product upon subsequent aging of solution tre2ted or solution treated and cold rolled material. When the alloys are water quenched from solution treatment, for example, cooled at average rates of 650C per minute or faster, one observes the dlscontinuous type (2) and possibly also the agglomerated type (1~ of Ni3Al precipitate in the aged product. ~aterial ;
which is water quenched from solution tre2~ment followed by cold rolllng and aging results in 2 mixture of all three r types of Mi3Al precipitates. When the alloys are slowly cooled from solution treatment, or example, at average rates of 80C per minute cr less, one observes type (3) of Ni3Al type precipitate formed as an array of extremely finely dispersed, ccherent particles. This is observed in the solution treated product per se or in the solution treated and aged product or in the solution tre~ted cold rolled and aged product. Alternatively, one may simply cool the solution annealed product directly to aging tem~erature, age at the aging temperature followed by cooling to room temperature, resulting in the foregoing type of precipitate (3).
Thus, ollowing solution annealing one may cool the material using 2 slow cooling mechanism or quenching mechanlsm as indicated hereinabove. In addition, one may age 3o the solution treated material at a temperature o from 250C
~Q~S7~
to 650C for times of from 30 mlnutes to 24 hours. The final condition of the materlal may be either solutlon treated, solutlon treated and aged, or solution treated, cold rolled and aged.
Alternatlvely, one may provide additional cold rolling after the aging treatment. This additional cold rolling results in additional strength but loss in formability and ductility.
For applications where maximum ductility is desired the alloy should be quenched after the solution anneal. Subse-quent cold rolling and aging generates both higher strength and better ductility thar. the as cold rolled metal. This improvement in both of these properties with aging is quite remarkable.
If maximum strength is desired rather than maximum ductility, the alloys should be slowly cooled from the solution anneal. Subsequent processing of this condition, including cold rolling and aging, results in increased strength with only slight loss in formability. It is quite surpris~ng that material slowly cooled from solution anneal-ing in this manner e~hibits an aging response. Thus, the alloys of the present invention may be processed to obtain a variety of properties related to con~rol of the cooling rate following the solution anneal at a temperature of from 650C
to 1100C. The aging step at tempera~ures of from 250C to 650C fcr times of from 3G minutes to 24 hours results in improved property combinations. The alloys may optionaliy be cold rolled, for example, up to 90~, between the solution anneal ard ~he aging steps, if desired, with the particular variations and the degree of rollirg depending upon the final 1(Pa\~756 property requirements.
Parts may be formed from cold rolled and/or aged materlal, with an optional heat treatment after forming. The heat treatment may be an aging treatment as above, or a low temper-ature thermal treatment at 150 - 300C for at least 15 minutes to enhance stress relaxation or stress corrosion resistance.
The present invention and i~.provements resulting therefrom will be more readily understandable from a consideration of the following illustrative examples. ~
EXAMPLE I - Tensile properties An alloy consisting of 15 wt. ,0 nickel and 2 wt. ~
aluminum, balance cop~er was cast from 1350C into a steel mold with a water-cooled copper base plate. The ten pound ingot was soaked at 1000C for four hours, immedlately hot rolled to 0.4" from 1.75" with a finishing temperatùre of about 500C and cold rolled to 0.120". The alloy was solution treated at 850C for one hour followed by water quenching to room te~.perature. The alloy was further processed to prov de metal at 0.020" gauge in the as-quenched and 20, 40, 60 and 83% cold rolled condltlon. Some metal was cold rolled directly to 0.020", that is, 83~ cold rolled metal. Some metal was cold rolled to 0.050" gauge again solution treated one hour at 850C and cold rolled to Q.020" gauge, i.e., 60%
cold rolled metal. Some metal was cold rolled to 0.033"
gauge, solution treated one hour at 850C and cold rolled to 0.020" gauge, i.e., 40~ cold rolled metal. Some metal was cold rolled to 0.025" gauge solution treated one hour at 850C and cold rolled to 0.020" gauge, i.e., 20% cold rolled metal. Some of the 60% cold rolled metal was solution treated at 850C/l hr. to provide solution treated metal, ~61 56 i.e., 0% reduction. After every solution treatment the metal was water quenched to room temperature. Some of each of the cold rolled metal at 0.020" was heat treated taged) at 400C
for 24 hours. Tensile propertles were measured for both the as-cold rolled and heat treated material. These tensile properties are listed in Table I. These properties are compared with those of the commercial high strength copper base alloys CDA 510 (4.4% tin, 0.07% phosphorus, balance copper) and CDA 638 ~2.7% aluminum, 1.7% silicon, 0.4% cobalt, balance copper). The data in Table I clearly demonstrate the significant heat treated strength and strength/ductility combination advantages obtained in accordance wit~ the alloy of the present invention. The microstructures of the aged materials of the present invention were examined and found to contain finely dispersed precipitates of Ni3Al particles dispersed throughout the matrix.
1~6756 Table I
Tensile Properties of Cu-15Ni-2Al Water ~uenched from the Solution Treatment Alloy % Cold 0.2~ Yield ~e ile Elongation Reduction StrenOt)h _ ns (%) Cu-15Ni-2A1 0 22 60 32.8 Cu-15Ni-2AlO+Aged 76 113 17.2 CDA 510 0 40 56 46.0 CDA 638 0 51 80 35.0 Cu-15Ni-2A1 20 59 66 13.3 Cu-15Ni-2A120+Aged 81 115 17.7 CDA 510 20 65 72 20.0 CDA 638 20 82 106 10.0 Cu-15Ni-2A1 40 78 81 1.0 Cu-15Ni-2A140~Aged 91 120 16.8 CDA 510 40 93 97 5.0 CDA 638 40 99 120 5.0 Cu-15Ni-2A1 60 84 86 1.3 Cu-15Ni-2A16~Aged 105 125 15.0 C3A 510 60 107 110 2.0 CDA 638 60 110 130 3.0 Cu-15Ni-2A1 83 90 92 1.0 Cu-15Ni-2A183+.~ed 118 141 14.0 CDA 510 83 114 120 1.0 CDA 638 83 118 139 1.0 - EXAMPLE II - ~ensile Properties An alloy consisting of 15 wt. ~c nicXel and 2 wt. ~
aluminum was cast and processed as described in E~ample I, except that the metal was air cooled to room temperature following each solution treatment. Again, the tensile properties were measured for both the as-cold rolled and heat treated (aged) condition. The microstructures of the solutior.
treated, solution treated and cold rolled, and solution treated, cold rolled and aged condl'ions o. the alloys of the present invention were exa~.ir.ed and found to contain finely dispersed precipitates of Ni3Al particles dispersed through-out the ~atrix. Compared with the propertles OL the two commercial high strength Allo~s 510 and 638 in Table I, the lQ467S6 data in Table II clearly demonstrates the significant rolled temper strength advantage as well as the heat treated strength advantages obtained in accordance with processing the alloy of the present invention in this way. It is particularly surprising that slowly cooled, heat treatable alloys can be cold rolled to such an extent as in this example without breaking up.
Table II
Tensile Properties of Cu-15Ni-2A1 Air-Cooled from the Solution Treatment Condition 0.2~ Yield UltimateElongation Strength Tensile (~) (ksi) Strength (ksi) Solution treated46 88 28.G
S.T. + Aged 52 92 19.7 CR 20do 128 133 4.8 CR 20% + Aged 132 137 2.9 CR 40% 132 142 1.0 CR 40~ + Aged 144 154 2.1 CR 60~ 131 142 2.0 CR 60% + Aged 148 158 2.1 CR 83d 125 139 3.5 CR 83~ + Aged 151 170 3.0 E~AMPLE III - Ber.d Formability Properties The bend for~ability of the Cu-15Ni-2Al alloy, processed as in Examples I and II, was evaluated. In particular, the 90 bend property for the heat treated (aged) condition was measured. The bend properties determine the minimum radius about which strip can be bent without crackir.g. ~nere the bend is made about ar. axis either perpendicular to or parallel 75~;
to the rolling direction, the longitudinal properties (goodway) refer to the axis perpendicular to the rolling directlon, while the transverse properties (badway) refer to the axis parallel to the rolling direction. MBR is the smallest radius which does not show cracks and t is the thickness of the strip, i.e., all at 0.020" gauge in this case. The resulting bend data are presented in Tables IIIA, IIIB, IIIC and IIID. Tables IIIA and IIIB compare the bend properties of Cu-15Ni-2Al that had been processed with water quenching and air cooling, respectively. Table IIIC compares the M~R/t available for Alloys 510 and 638 with the MBR/t for an alloy of the present invention. Surpr~singly, for a giver strength level, the heat treated alloy of the present invention offers greater bend fcrmability, either goodway or badway, i.e., lower MBR/t, thar do Alloys 510 and 638. Table IIID is a similar comparison showing the higher yield strength available at a given MBR/t for the alloys of this invention compared to Alloys 510 and 638. It is co~.ercially desirable to obtain higher strength for a given bend radius and the heat treated Cu-15Ni-2Al alloy offers greater strength for a given bend radius, especially in the critical badway mode, than the high strength commercial wrought Alloys 510 and 638. It is particularly significant that the alloy of the present invention has adequate bend ductility at strength levels the other alloys cannot attain.
3o Table IIIA
Bend Properties of Cold Rolled And Aged Cu-15Ni-2Al, That Had Been Water Quenched From The Solution Treatment Temperature Minimum Bend Radius / thickness Condition* Aged 0.2% YS, Cu-15Ni-2Al ksi G.W. B.W.
Quenched + Aged76 sharp sharp - 10 CR 20% + Aged 81 0 . 4 1. 6 CR 40% + Aged 91 0. 4 0 . 4 CR 60% + Aged105 0. 8 1. 6 CR 83~o + Aged118 7.8 9.4 * Aged 400C-24 hrs. at 0.020" gauge Table IIIB
Bend Properties o~ Cold Rolled And Aged Cu-15Ni-2Al, That Had Been Air Cooled From The Solution Treatment Tem~erature -Minlmum Bend Radius / thicXness Condition* Aged 0.2~ YS, Cu-15~i-2Al ksi G.W. B.W.
Cooled + Aged 52 sharp sharp CR 20~ + Aged132 6.2 5.5 CR 40~ + Aged144 6.2 5.5 CR 60~ + Aged148 6.2 7.8 CR 83~ + Aged151 7.8 12.5 * .4ged 400C-24 hrs. at Q.020" gauge 6~S6 Table IIIC
Comparison of Bend Properties of Cold Rolled And Aged Cu-15Ni-2Al With Those of Temper Rolled CDA 510 And 638 Minimum Bend Radius / thickness 0.2~ Yield Cu-15Ni-2A1 510 638 Strength, ksi G _ B.W. G.W. B.W. G.W. B.W._ 0.2 0.2 0.2 1.6 0.8 2.1 0.4 0.4 0.4 3.2 1.5 3.3 100 0.7 1.1 1.0 4.3 2.2 4.3 110 1.4 2.0 1.8 9.0 3.2 10.0 120 2.4 3.2 _ _ 4.8 >25 130 4.2 5.0 - - - -140 5.7 7.0 Table IIID
Comparison o~ Strength/Ber.d Property Combinations of Cold Rolled And Aged Cu-l~N~-2Al With Those of ~emper Rolled C~A 510 And CDA 638 0.2% Yield St~ength, ksi Goodway Aged Cold RolledCold Rolled MBRf~ Cu-15Ni-2A1 510 638
3 123 - 107
4 129 - 117 Badway ~IBR/t lQ~6756 EXAMPLE IV - High Strength Bend Formability The surprising advantage of the alloy of the present invention is that in the high strength aged condition it provides excellent strength~ductility combinations. This effect is not observed with the commercially available high strength, age hardening copper base alloys such as beryllium-copper and Cu-9Ni-6Sn (nominal). To take advantage of their high strength capabilities, these latter two alloys are also solution treated, cold rolled and aged. But a part that must be formed with a pressing or bending operation, such as would be required by a typical electrical conta~t spring component, must be formed in the cold rolled condi~ion and aged after the part is formed. In practice, this latter procedure requires that the formed co~ponent be adequately supported with expensive fixture arrangements to avoid the unwPnted distortion that occurs during the aging treatment. An alternative approach ls to cold roll the solution treated conditions ar.d underage the strip so that adequate bend formability at reasonable strength would be attained without a post-forming heat treatment. But, this latter process results in under-utilization of the strength capability of these expensive materials. The advantage of the alloy o~ the present invention ls that adequate bend formability is achieved when the solution treated and cold worked material is heat treated (aged) to high strength. This latter situaticn allows ~he full utilization of the high strength aiong with adequate bend formability. Table IV shows this advantage by comparing tensile and bend data for Cu-15Ni-2Al, beryllium-copper and a Cu-9Ni-6Sn alloy.
1C! ~675~;
Table I~
Mechanical Properties of High Strength Copper Alloys Alloy and 0.2% Ultimate Elongation MBR/t Condition YS Tensile ~ Cood~ay Badway (ksi) Strength _ (ksi) Cu-15Ni-2Al Cold Rolled 40% 132 142 1.0 3.9 5.0 Aged 400C-24 hrs. 144 154 2.1 6.2 5.0 Cu-11.9Ni-4.8Sn Cold Rolled 112 122 2.7 2.8 2.8 Aged 134 142 5.0 11.1>11.1 CDA 172 (Cu_l.9~e-0.2Co) Cold Rolled +
Underaged 107 135 14.8 1.2 1.5 EXA~PLE ~ igh Strength Copper-Nickel-Aluminum Base Allcys To show the high strength provided by quarternary and quinary additions to a 15Ni-2Al composition as l~ell as deviations frcm these nickel and alum.inum contents in the ternary copper alloy, the tensile data in Table ~ are presented. These properties were measured on these 2110ys in the solution treated, cold rolled and heat treated conditions The alloys had been processed (cast and hot rolled and cold rolled) according to the processing described in Examples I
and II. The solution treatment temperature was 1000C. The microstructures o~ all materials were examined and ~ound to contain ~inely dispersed precipitates of Ni3Al particles dispersed throughout the matrix. In addition, the micro-structures o~ the chromium, vanadium and titan'um containing alloys showed the presence o~ second precipitate particles as described above.
Table V
Tensile Properties of Various Solution Treated-Cold Rolled and Heat Treated (Aged) Copper-Nickel-Aluminum Base Alloys Alloy 0.2% Yield Ultimate Elongation Strength Tensile (%) (ksi) Strength (ksi) Cu-15Ni-2Al-2Cr 150 168 1.6 Cu-20Ni-3A1 176 193 o.8 Cu-15Ni-2Al-6Fe 160 180 2.0 Cu-15Ni-2Al-2Cr-0.5 Ti 171 184 0.3 Cu-15Ni-2Al-1~ 166 185 5.0 Cu-15Ni-3A1 155 193 2.7 This invention may be embodied in other forms or carried out in other ways without departing from the spirit or essential characteristics thereof. The present em~cdiment i3 therefore to be considered as in all respects illustrative and not restrictive, the scope of the invention being indicated by the appended claims, and all chang_s ~hich come wlthin the meaning and range of equivalency are intended to be embraced therein.
1C! ~675~;
Table I~
Mechanical Properties of High Strength Copper Alloys Alloy and 0.2% Ultimate Elongation MBR/t Condition YS Tensile ~ Cood~ay Badway (ksi) Strength _ (ksi) Cu-15Ni-2Al Cold Rolled 40% 132 142 1.0 3.9 5.0 Aged 400C-24 hrs. 144 154 2.1 6.2 5.0 Cu-11.9Ni-4.8Sn Cold Rolled 112 122 2.7 2.8 2.8 Aged 134 142 5.0 11.1>11.1 CDA 172 (Cu_l.9~e-0.2Co) Cold Rolled +
Underaged 107 135 14.8 1.2 1.5 EXA~PLE ~ igh Strength Copper-Nickel-Aluminum Base Allcys To show the high strength provided by quarternary and quinary additions to a 15Ni-2Al composition as l~ell as deviations frcm these nickel and alum.inum contents in the ternary copper alloy, the tensile data in Table ~ are presented. These properties were measured on these 2110ys in the solution treated, cold rolled and heat treated conditions The alloys had been processed (cast and hot rolled and cold rolled) according to the processing described in Examples I
and II. The solution treatment temperature was 1000C. The microstructures o~ all materials were examined and ~ound to contain ~inely dispersed precipitates of Ni3Al particles dispersed throughout the matrix. In addition, the micro-structures o~ the chromium, vanadium and titan'um containing alloys showed the presence o~ second precipitate particles as described above.
Table V
Tensile Properties of Various Solution Treated-Cold Rolled and Heat Treated (Aged) Copper-Nickel-Aluminum Base Alloys Alloy 0.2% Yield Ultimate Elongation Strength Tensile (%) (ksi) Strength (ksi) Cu-15Ni-2Al-2Cr 150 168 1.6 Cu-20Ni-3A1 176 193 o.8 Cu-15Ni-2Al-6Fe 160 180 2.0 Cu-15Ni-2Al-2Cr-0.5 Ti 171 184 0.3 Cu-15Ni-2Al-1~ 166 185 5.0 Cu-15Ni-3A1 155 193 2.7 This invention may be embodied in other forms or carried out in other ways without departing from the spirit or essential characteristics thereof. The present em~cdiment i3 therefore to be considered as in all respects illustrative and not restrictive, the scope of the invention being indicated by the appended claims, and all chang_s ~hich come wlthin the meaning and range of equivalency are intended to be embraced therein.
Claims (13)
1. A method for obtaining a spinodal, precipitation hardened copper base alloy having high strength and favorable strength to ductility characteristics which comprises:
(A) providing a copper base alloy consisting essentially of:
(1) 10 to 30% bt weight nickel (2) from 1 to 5% by weight aluminum;
(3) from 0% to 20% by weight of an element selected from the group consisting of zinc, iron, tin, titanium, zirconium, hafnium, beryllium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, and mixtures thereof;
(4) from 0% to 5% by weight of an element selected from the group consisting of lead, arsenic, antimony, boron, phosphorus, manganese, silicon, a lanthanide metal, magnesium, lithium, and mixtures thereof; and (5) the balance being copper;
(B) hot working said alloy with a finishing temperature in excess of 400°C;
(c) solution annealing said alloy for from 10 seconds to 24 hours at a temperature of from 650 to 1100°C; and (D) cooling the alloy to room temperature; thereby to provide a spinodal, precipitation hardened copper base alloy wherein the microstructure is characterized by the presence of finely dispersed precipitates of Ni3Al particles dispersed throughout the matrix.
(A) providing a copper base alloy consisting essentially of:
(1) 10 to 30% bt weight nickel (2) from 1 to 5% by weight aluminum;
(3) from 0% to 20% by weight of an element selected from the group consisting of zinc, iron, tin, titanium, zirconium, hafnium, beryllium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, and mixtures thereof;
(4) from 0% to 5% by weight of an element selected from the group consisting of lead, arsenic, antimony, boron, phosphorus, manganese, silicon, a lanthanide metal, magnesium, lithium, and mixtures thereof; and (5) the balance being copper;
(B) hot working said alloy with a finishing temperature in excess of 400°C;
(c) solution annealing said alloy for from 10 seconds to 24 hours at a temperature of from 650 to 1100°C; and (D) cooling the alloy to room temperature; thereby to provide a spinodal, precipitation hardened copper base alloy wherein the microstructure is characterized by the presence of finely dispersed precipitates of Ni3Al particles dispersed throughout the matrix.
2. A method according to Claim 1 wherein said alloy includes a total of up to 20% by weight of an element selected from the group consiting of iron, tin, titanium, zirconium, hafnium, beryllium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten and mixtures thereof, said zinc, iron and tin, when present, each being present in an amount of from 0.01 to 10% by weight of the alloy, and said titanium, zirconium, hafnium, beryllium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten and mixtures thereof, (when present) each being present in an amount ranging from 0.01%
to 5% by weight of the alloy; and wherein the resultant microstructure is characterized by the presence of second precipitate particles.
to 5% by weight of the alloy; and wherein the resultant microstructure is characterized by the presence of second precipitate particles.
3. A method according to Claim 1 wherein said alloy includes a total of up to 5% of an element selected from the group consisting of lead, arsenic, atimony, boron, phosphorus, manganese, silicon, a lanthanide metal, magnesium, lithium and mixtures thereof, with each of said elements, when present, being present in an amount of from 0.001 to 3%, said percentages being by weight based on the alloy.
4. A method according to Claim 1 wherein said alloy is homogenized prior to hot working at a temperature between 600°C and the solidus temperature of the alloy for at least 15 minutes.
5. A method according to Claim 1 wherein said alloy is cold worked following hot working but before solution annealing.
6. A method according to Claim 5 wherein all working steps are rolling.
7. A method according to Claim 6 wherein said alloy is cold rolled with intermediate annealing at from 250°C to within 50°C of the solidus temperature for from 10 seconds to 24 hours.
8. The method according to Claim 1 wherein said alloy is water quenched following solution annealing.
9. A method according to Claim 8 wherein the alloy is aged following quenching at a temperature of from 250 to 650°C for from 30 minutes to 24 hours.
10. A method according to Claim 9 wherein the alloy is cold rolled and aged following quenching.
11. A method according to Claim 1 wherein the alloy is slowly cooled following solution annealing.
12. A method according to Claim 11 wherein the alloy is aged following slowly cooling at a temperature of from 250 to 650°C for from 30 minutes to 24 hours.
13. A method according to Claim 12 wherein the alloy is cold rooled and aged following slowly cooling.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US65591876A | 1976-02-06 | 1976-02-06 | |
| US655,791 | 1976-02-06 | ||
| US655,918 | 1976-02-06 | ||
| US05/655,791 US4016010A (en) | 1976-02-06 | 1976-02-06 | Preparation of high strength copper base alloy |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1096756A true CA1096756A (en) | 1981-03-03 |
Family
ID=27097037
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA270,907A Expired CA1096756A (en) | 1976-02-06 | 1977-02-02 | High strength copper base alloy and preparation thereof |
Country Status (8)
| Country | Link |
|---|---|
| JP (1) | JPS5295531A (en) |
| AU (1) | AU505951B2 (en) |
| CA (1) | CA1096756A (en) |
| DE (1) | DE2704765A1 (en) |
| FR (2) | FR2421953A1 (en) |
| GB (1) | GB1520721A (en) |
| IT (1) | IT1082683B (en) |
| SE (1) | SE7701271L (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5004581A (en) * | 1989-07-31 | 1991-04-02 | Toyota Jidosha Kabushiki Kaisha | Dispersion strengthened copper-base alloy for overlay |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2123852B (en) * | 1982-07-19 | 1986-06-11 | Gen Electric | Electrode contacts for high currant circuit interruption |
| JPS63250434A (en) * | 1987-04-08 | 1988-10-18 | Dowa Mining Co Ltd | Copper-base alloy for connector |
| US5087416A (en) * | 1989-10-12 | 1992-02-11 | Gte Products Corporation | Brazing alloy of copper, silicon, titanium, aluminum |
| US9476474B2 (en) * | 2010-12-13 | 2016-10-25 | Nippon Seisen Co., Ltd. | Copper alloy wire and copper alloy spring |
| MX370072B (en) | 2012-10-26 | 2019-11-29 | Sloan Valve Co | White antimicrobial copper alloy. |
| CN104532055A (en) * | 2014-11-21 | 2015-04-22 | 华南理工大学 | High nickel-content deformable aluminum white copper alloy material, and preparation method thereof |
| CN104630555A (en) * | 2015-03-10 | 2015-05-20 | 济南大学 | High-strength corrosion resisting brass material and preparation method thereof |
| CN106756219B (en) * | 2016-12-12 | 2018-08-28 | 武汉利振达机电有限公司 | A kind of cupro-nickel vanadium catalyst alloy for scale inhibition |
| CN107653384A (en) * | 2017-08-31 | 2018-02-02 | 宋宏婷 | A kind of preparation method of in-situ preparation nickel aluminide enhancing Cu-base composites |
| JP7202121B2 (en) | 2018-09-27 | 2023-01-11 | Ｄｏｗａメタルテック株式会社 | Cu-Ni-Al-based copper alloy plate material, manufacturing method thereof, and conductive spring member |
| JP7181768B2 (en) * | 2018-11-13 | 2022-12-01 | Ｄｏｗａメタルテック株式会社 | High Young's Modulus Cu--Ni--Al Copper Alloy Plate Material, Manufacturing Method Thereof, and Conductive Spring Member |
| CN110358945B (en) * | 2019-08-27 | 2020-10-30 | 天长市华海电子科技有限公司 | High-hardness alloy forging piece and preparation process thereof |
| DE102020007257A1 (en) * | 2020-11-27 | 2022-06-02 | Wieland-Werke Aktiengesellschaft | Copper-nickel cast alloy |
| CN115044747B (en) * | 2022-05-16 | 2023-02-10 | 上海交通大学 | Heat treatment process method for improving strength and toughness of nickel-aluminum bronze alloy |
| CN116043061A (en) * | 2023-01-18 | 2023-05-02 | 中南大学 | Elastic copper alloy and preparation method thereof |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR742648A (en) * | 1933-03-10 | |||
| GB191408270A (en) * | 1914-04-01 | 1915-04-01 | George Albert Joyce | Improvements relating to Alloys or Nickel, Copper, and Aluminium, with or without Steel. |
| US1496269A (en) * | 1921-01-07 | 1924-06-03 | Mitsubishi Zosen Kaisha Ltd | Alloy |
| FR724019A (en) * | 1931-07-23 | 1932-04-19 | Mond Nickel Co Ltd | Improvements to alloys for tubes and other condenser components subjected to corrosive action |
| DE655931C (en) * | 1933-08-17 | 1938-01-27 | Eugen Vaders Dr | Payable copper-nickel alloy |
| GB425547A (en) * | 1933-09-16 | 1935-03-18 | Henry Winder Brownsdon | Improvements in or relating to the manufacture of springs and like resilient metal articles |
| FR911151A (en) * | 1939-01-13 | 1946-07-01 | Ici Ltd | Improvements to copper alloys |
| DE1458450A1 (en) * | 1962-08-02 | 1969-09-18 | Kabel Metallwerke Ghh | Aluminum-containing copper-nickel cast alloy for self-hardening castings with improved form changeability |
| DE1558471A1 (en) * | 1967-02-03 | 1970-03-19 | Dies Dr Ing Kurt | Copper alloy for valve guide |
| SU405964A1 (en) * | 1971-09-27 | 1973-11-05 | COPPER BASED ALLOY |
-
1977
- 1977-02-02 GB GB421577A patent/GB1520721A/en not_active Expired
- 1977-02-02 CA CA270,907A patent/CA1096756A/en not_active Expired
- 1977-02-04 SE SE7701271A patent/SE7701271L/en not_active Application Discontinuation
- 1977-02-04 DE DE19772704765 patent/DE2704765A1/en not_active Withdrawn
- 1977-02-04 IT IT4793377A patent/IT1082683B/en active
- 1977-02-04 AU AU21973/77A patent/AU505951B2/en not_active Expired
- 1977-02-04 JP JP1155677A patent/JPS5295531A/en active Pending
- 1977-02-04 FR FR7703255A patent/FR2421953A1/en active Granted
-
1979
- 1979-03-15 FR FR7906640A patent/FR2422727A1/en not_active Withdrawn
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5004581A (en) * | 1989-07-31 | 1991-04-02 | Toyota Jidosha Kabushiki Kaisha | Dispersion strengthened copper-base alloy for overlay |
Also Published As
| Publication number | Publication date |
|---|---|
| AU505951B2 (en) | 1979-12-06 |
| FR2421953B1 (en) | 1982-07-16 |
| GB1520721A (en) | 1978-08-09 |
| FR2422727A1 (en) | 1979-11-09 |
| SE7701271L (en) | 1977-08-07 |
| JPS5295531A (en) | 1977-08-11 |
| FR2421953A1 (en) | 1979-11-02 |
| IT1082683B (en) | 1985-05-21 |
| DE2704765A1 (en) | 1977-08-11 |
| AU2197377A (en) | 1978-08-10 |
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