Copper alloys having an improved combination of strength and conductivity

Claim 2

A copper base alloy having a combination of high strength and high conductivity consisting essentially of from about 0.3 to about 1.6% by weight iron, with up to one-half the iron content being replaced by an element selected from the group consisting of nickel, manganese, cobalt and mixtures thereof; from about 0.01 to about 0.20% by weight magnesium; from about 0.10 to about 0.40% by weight phosphorus; up to about 0.5% by weight of an element selected from the group consisting of tin, antimony, and mixtures thereof; and the balance copper; with the proviso that the phosphorus to magnesium ratio comprises at least about 2.5 and that the ratio of phosphorus to the total content of phosphide formers (magnesium+iron+nickel+manganese+cobalt) ranges from about 0.22 to about 0.49.

Claim 3

A copper base alloy as in claim 1 wherein said iron content is from at least about 0.35% to about 1.6% by weight.

Claim 4

A copper base alloy as in claim 1 wherein said alloy consists essentially of from about 0.5 to about 1.0% by weight iron, with up to one-half the iron content being replaced by an element selected from the group consisting of nickel, manganese, cobalt and mixtures thereof; from about 0.15 to about 0.25% by weight phosphorus; from about 0.02 to about 0.1% by weight magnesium; up to about 0.35% by weight of an element selected from the group consisting of tin, antimony, and mixtures thereof; and the balance copper; with the proviso that the phosphorus to magnesium ratio ranges from about 2.5 to about 8.0 and that the ratio of phosphorus to the total content of phosphide formers ranges from about 0.25 to about 0.44.

Claim 5

A copper base alloy as in claim 1 wherein tin is present in an effective amount for increasing the strength of the alloy up to about 0.4% by weight and with the proviso that the ratio of phosphorus to the total content of phosphide formers ranges from about 0.22 to about 0.48.

Claim 6

A copper base alloy as in claim 4 wherein said ratio of phosphorus to the total content of phosphide formers ranges from about 0.22 to about 0.48.

Claim 7

A copper base alloy as in claim 3 wherein tin is present in an amount from 0.05 to about 0.35% by weight and with the proviso that the ratio of phosphorus to the total content of the phosphide formers ranges from about 0.27 to about 0.39.

Claim 8

A copper base alloy as in claims 1, 2 or 3 comprising a lead frame.

Claim 9

A copper base alloy as in claims 1, 2 or 3 which is essentially free of silicon.

Claim 10

A copper base alloy as in claims 1, 2 or 3 which is essentially free of silicon, aluminum and chromium.

Claim 11

A copper base alloy as in claims 1 or 4 wherein said alloy contains a mixture of phosphides comprising magnesium phosphide particles and phosphide particles of iron with or without an element selected from the group consisting of nickel, manganese, cobalt or mixtures thereof.

Claim 12

A copper base alloy as in claims 1 or 4 wherein the microstructure of the alloy consists essentially of some large 1 to 3 micron phosphide particles and a uniform dispersion of fine phosphide particles of less than about 0.5 microns in size.

Claim 13

A copper base alloy as in claims 4, 5 or 6 comprising an electrical connector.

Claim 14

A copper base alloy as in claim 1 wherein said ratio of phosphorus to magnesium ranges from about 3.0 to about 6.0.

Claim 15

A process for making a copper base alloy comprising: providing a copper base alloy consisting essentially of from about 0.3 to about 1.6% by weight iron, with up to one-half the iron content being replaced by an element selected from the group consisting of nickel, manganese, cobalt and mixtures thereof; from about 0.01 to about 0.20% by weight magnesium; from about 0.10 to about 0.40% by weight phosphorus; up to about 0.5% by weight of an element selected from the group consisting of tin, antimony, and mixtures thereof; and the balance copper; with the proviso that the phosphorus to magnesium ratio comprises at least about 2.5 and that the ratio of phosphorus to the total content of phosphide formers (magnesium+iron+nickel+manganese+cobalt) ranges from about 0.22 to about 0.49; hot working said alloy from a starting temperature of from about 850° to about 980° C. to a desired gauge; cold working said alloy from about 10 to about 90%; and annealing said alloy at a temperature of from about 400° C. to about 800° C. for an effective period of time to soften said alloy up to about 6 hours.

Claim 16

A process for making a copper base alloy comprising: providing a copper base alloy consisting essentially of from about 0.3 to about 1.6% by weight iron, with up to one-half the iron content being replaced by an element selected from the group consisting of nickel, manganese, cobalt and mixtures thereof; from about 0.01 to about 0.20% by weight magnesium; from about 0.10 to about 0.40% by weight phosphorus; up to about 0.5% by weight of an element selected from the group consisting of tin, antimony, and mixtures thereof; and the balance copper; with the proviso that the phosphorus to magnesium ratio comprises at least about 2.5 and that the ratio of phosphorus to the total content of phosphide formers (magnesium+iron+nickel+manganese+cobalt) ranges from about 0.22 to about 0.49; hot working said alloy from a starting temperature of from about 850° to about 980° C. to a desired gauge; cold working said alloy from about 10 to about 90%; and annealing said alloy at a temperature of from about 400° C. to about 800° C. for an effective period of time to soften said alloy up to about 6 hours.

Claim 17

A process as in claim 14 wherein said alloy is further cold worked from about 10 to about 90% and then annealed at a temperature of from about 350° to about 550° C.

Claim 18

A process as in claim 14 wherein said annealed alloy is further cold worked from about 20 to about 80% to provide a desired temper.

Claim 19

A process as in claim 14 wherein said iron content is from at least about 0.35% to about 1.6% by weight.

Claim 20

A process as in claims 14 or 15 wherein said alloy consists essentially of from about 0.5 to about 1.0% by weight iron, with up to one-half the iron content being replaced by an element selected from the group consisting of nickel, manganese, cobalt and mixtures thereof; from about 0.15 to about 0.25% by weight phosphorus; from about 0.02 to about 0.1% by weight magnesium; up to about 0.35% by weight of an element selected from the group consisting of tin, antimony, and mixtures thereof; and the balance copper; with the proviso that the phosphorus to magnesium ratio ranges from about 2.5 to about 8.0 and that the ratio of phosphorus to the total content of phosphide formers ranges from about 0.25 to about 0.44.

Claim 21

A process as in claims 14 or 15 wherein tin is present in an effective amount for increasing the strength of the alloy up to about 0.4% by weight and with the proviso that the ratio of phosphorus to the total content of phosphide formers is from about 0.22 to about 0.48.

Claim 22

A process as in claims 14 or 15 wherein said ratio of phosphorus to the total content of phosphide formers is from about 0.24 to about 0.48.

Claim 23

A process as in claims 14 or 15 wherein tin is present in an amount from 0.05 to about 0.35% by weight and with the proviso that the ratio of phosphorus to the total content of phosphide formers ranges from about 0.27 to about 0.39.

Claim 24

A process as in claim 14 for providing an alloy having improved strength wherein said annealing step comprises an anneal for partial recrystallization and wherein said anneal is carried out at a temperature of from about 425° to about 500° C. so as to provide from about 10 to about 80% recrystallization of said alloy.

Claim 25

A process as in claim 22 wherein said alloy is further cold worked from about 10 to about 90% and then annealed to provide partial recrystallization of from about 10 to about 80% recrystallization of said alloy at a temperature of from about 375° to about 475° C.

Claim 26

A process as in claim 16 further including the step of forming said alloy into a semiconductor lead frame.

Claim 27

A process as in claim 16 wherein tin is present in an effective amount for increasing the strength of the alloy up to about 0.4% by weight and with the proviso that the ratio of phosphorus to the total content of phosphide formers is from about 0.24 to about 0.48 and further including the step of forming said alloy into an electrical connector.