Copper-nickel-tin-cobalt spinodal alloy

Claim 2

A copper base spinodal alloy consisting essentially of from about 5 to about 30 percent by weight nickel, from about 4 to about 13 percent by weight tin, from about 3.5 to about 7 percent by weight cobalt and the balance copper, with the sum of the nickel and cobalt contents being no more than 35 percent by weight of the alloy.

Claim 3

An alloy of claim 1 wherein the tin content thereof is at least about 8.5 percent by weight and the sum of the nickel and cobalt contents is at least 20 percent by weight of the alloy.

Claim 4

An alloy of claim 2 wherein the tin content thereof is from about 8.5 to about 11 percent by weight and the nickel content thereof is from about 20 to about 25 percent by weight thereof.

Claim 5

An age hardened spinodally decomposed alloy of claim 1.

Claim 6

An age hardened spinodally decomposed alloy of claim 2.

Claim 7

An age hardened spinodally decomposed alloy of claim, 3.

Claim 8

An alloy of claim 6, further characterized in that said alloy has an electrical conductivity of at least 4% IACS, a tensile yield stress (0.2% offset) of at least 140 ksi and a percent elongation (1 inch gage length) at its tensile break point of at least 2 percent.

Claim 9

An alloy of claim 4 that has been cold worked, in such a manner as to achieve a cross-sectional area reduction of at least about 5 percent, immediately prior to age hardening.

Claim 10

An alloy of claim 5 that has been cold worked, in such a manner as to achieve a cross-sectional area reduction of at least about 5 percent, immediately prior to age hardening.

Claim 11

An alloy of claim 6 that has been cold worked, in such a manner as to achieve a cross-sectional area reduction of at least about 5 percent, immediately prior to age hardening.

Claim 12

An alloy of claim 1 wherein the tin content thereof is from about 6 to about 8.5 percent by weight and the sum of the nickel and cobalt contents is no more than 20 percent by weight of the alloy.

Claim 13

An age hardened spinodally decomposed alloy of claim 11.

Claim 14

An alloy of claim 12 that has been cold worked, in such a manner as to achieve a cross-sectional area reduction of at least about 5 percent, immediately prior to age hardening.

Claim 15

An article of manufacture comprising the alloy of claim 1.

Claim 16

An alloy strip consisting essentially of the alloy of claim 1.

Claim 17

A process for preparing a copper base spinodal alloy body which comprises: (a) providing a copper base alloy powder containing from about 5 to about 30 percent by weight nickel, from about 4 to about 13 percent by weight tin, from about 3.5 to about 7 percent by weight cobalt, and the balance copper, with the sum of the nickel and cobalt contents being no more than 35 percent by weight of the powder; (b) compacting the alloy powder to form a green body having structural integrity and sufficient porosity to be penetrated by a reducing atmosphere; (c) sintering the green body in the reducing atmosphere to form a metallurgical bond; and (d) cooling the sintered body at a rate such that age hardening and embrittlement are prevented.

Claim 18

A process for preparing a copper base spinodal alloy body which comprises: (a) providing a copper base alloy powder containing from about 5 to about 30 percent by weight nickel, from about 4 to about 13 percent by weight tin, from about 3.5 to about 7 percent by weight cobalt, and the balance copper, with the sum of the nickel and cobalt contents being no more than 35 percent by weight of the powder; (b) compacting the alloy powder to form a green body having structural integrity and sufficient porosity to be penetrated by a reducing atmosphere; (c) sintering the green body in the reducing atmosphere to form a metallurgical bond; and (d) cooling the sintered body at a rate such that age hardening and embrittlement are prevented.

Claim 19

A process of claim 16 wherein the alloy powder is compacted to at least about twice its original uncompacted density.

Claim 20

A process of claim 16 wherein the density of the green body is from about 70 to 95 percent of the theoretical density of said body.

Claim 21

A process of claim 16 wherein the sintering is at a temperature of from about 1400° F. to about 1900° F. for at least about one minute.

Claim 22

A process of claim 19 wherein the sintering is at a temperature of from about 1600° F. to about 1700° F.

Claim 23

A process of claim 16 wherein the sintered body is cooled below the age hardening temperature range of the alloy at a rate of at least about 200° F. per minute.

Claim 24

A process of claim 16 wherein the oxygen and carbon contents of the sintered body are each kept to less than about 100 ppm.

Claim 25

A process of claim 16 wherein said green body, said sintered body and said alloy body are each in the form of a strip.

Claim 26

A process of claim 16 comprising additionally: (e) working the sintered body to a substantially fully dense condition; and (f) annealing the worked body and quenching it at a rate sufficient to retain substantially all alpha phase.

Claim 27

A process of claim 24 wherein the sintered body is cold worked in said step (e).

Claim 28

A process of claim 25 wherein said cold working results in a reduction of at least about 30 percent of cross-sectional area.

Claim 29

A process of claim 24 wherein the final anneal is at a temperature of from about 1500° F. to about 1700° F. for at least about 15 seconds, followed by quenching at a rate of at least about 100° F. per second to retain substantially all alpha phase.

Claim 30

A process of claim 24 wherein the alloy body is age hardened following the final anneal and quench.

Claim 31

A process of claim 28 wherein the age hardening is at a temperature of from about 500° F. to about 1000° F. for at least about 15 seconds.

Claim 32

A process of claim 29 wherein the duration of the age hardening treatment is approximately equal to the peak strength aging time of the alloy at the age hardening temperature.

Claim 33

A process of claim 28 wherein the alloy body is cold worked to achieve at least about a 5 percent reduction in cross-sectional area after the final anneal and quench but before the age hardening.

Claim 34

A process of claim 31 wherein the alloy body is cold worked to achieve at least about a 15 percent reduction in cross-sectional area after the final anneal and quench but before the age hardening.

Claim 35

A process of claim 24 wherein said green body, said sintered body, said alloy body and said worked body are each in the form of a strip.

Claim 36

A process of claim 28 wherein said green body, said sintered body, said worked body and said alloy body are each in the form of a strip.

Claim 37

A process of claim 24 wherein the annealed and quenched body is characterized by an equiaxed grain structure of substantially all alpha, face-centered-cubic phase with a substantially uniform dispersed concentration of tin and a substantial absence of tin segregation, and by a substantial absence of grain boundary precipitation.