US5455003A — Al-Cu-Li alloys with improved cryogenic fracture …

Claim 1

Independent Claim 112 words

A method for producing an improved aluminum-base alloy comprising the steps of: a) providing a solution heat treated and quenched aluminum-base alloy consisting essentially of from 2.0 to 6.5 weight percent Cu, from 0.2 to 2.0 weight percent Li, and the balance aluminum and incidental impurities; and b) at least one of working and artificially aging said alloy in an amount sufficient to provide strength and fracture toughness to said alloy at cryogenic temperature substantially equal to or greater than the strength and fracture toughness at room temperature, wherein the fracture toughness at room temperature is at least 18.7 ksi√in and the fracture toughness at -196° C. is at least 19.2 ksi√in.

Claim 2

Independent Claim 112 words

A method for producing an improved aluminum-base alloy comprising the steps of: a) providing a solution heat treated and quenched aluminum-base alloy consisting essentially of from 2.0 to 6.5 weight percent Cu, from 0.2 to 2.0 weight percent Li, and the balance aluminum and incidental impurities; and b) at least one of working and artificially aging said alloy in an amount sufficient to provide strength and fracture toughness to said alloy at cryogenic temperature substantially equal to or greater than the strength and fracture toughness at room temperature, wherein the fracture toughness at room temperature is at least 18.7 ksi√in and the fracture toughness at -196° C. is at least 19.2 ksi√in.

Claim 3

Dependent Claim 52 words

A method according to claim 1, wherein said aluminum-base alloy further contains Mg in an amount up to 40. weight percent and from 0.01 to 1.0 weight percent of at least one grain refiner selected from the group consisting of Zr, Ti, Cr, Mn, Hf, Nb, B, V, and TiB 2 .

Claim 4

Dependent Claim 44 words

A method according to claim 1, wherein said aluminum-base alloy further contains at least one of Ag in an amount up to 4.0 weight percent, Mg in an amount up to 4.0 weight percent, and Zn in an amount up to 3.0 weight percent.

Claim 5

Dependent Claim 44 words

A method according to claim 2, wherein said aluminum-base alloy further contains at least one of Ag in an amount up to 4.0 weight percent, Mg in an amount up to 4.0 weight percent, and Zn in an amount up to 3.0 weight percent.

Claim 6

Dependent Claim 18 words

A method according to claim 1, wherein said working of said alloy is performed substantially at room temperature.

Claim 7

Dependent Claim 28 words

A method according to claim 1, wherein said working of said alloy is achieved by introducing the equivalent of from 3 to 7 percent stretch to said alloy.

Claim 8

Dependent Claim 44 words

A method according to claim 1, wherein the time and temperature at which said artificial aging is performed results in underaging of said alloy to a yield strength at least 5 ksi below the peak yield strength that said alloy is capable of attaining.

Claim 9

Dependent Claim 21 words

A method according to claim 1, wherein said artificial aging is performed at a temperature of from 125° to 150° C.

Claim 10

Dependent Claim 41 words

A method according to claim 1, wherein said Cu comprises from 2.8 to 4.8 weight percent, said Li comprises from 0.4 to 1.5 weight percent, and furthermore comprises Mg in an amount from 0.2 to 1.0 weight percent of said alloy.

Claim 11

Dependent Claim 45 words

A method according to claim 2, wherein said Cu comprises from 2.8 to 4.8 weight percent, said Li comprises from 0.4 to 1.5 weight percent, and the aluminum base alloy furthermore comprises Mg in an amount from 0.2 to 1.0 weight percent of said alloy.

Claim 12

Dependent Claim 35 words

A method according to claim 9, wherein said aluminum-base alloy further contains at least one of Ag in an amount up to 0.8 weight percent and Zn in an amount up to 1.0 weight percent.

Claim 13

Dependent Claim 35 words

A method according to claim 10, wherein said aluminum-base alloy further contains at least one of Ag in an amount up to 0.8 weight percent and Zn in an amount up to 1.0 weight percent.

Claim 14

Dependent Claim 64 words

A method according to claim 4, wherein said Cu comprises from 3.0 to 4.5 weight percent, said Li comprises from 0.7 to 1.1 weight percent, said Mg comprises from 0.3 to 0.6 weight percent, and said grain refiner comprises from 0.08 to 0.3 weight percent of said alloy, wherein said grain refiner is selected from the group consisting of Zr, Ti, and combinations thereof.

Claim 15

Dependent Claim 45 words

A method according to claim 2, wherein said Cu comprises from 2.8 to 4.8 weight percent, said Li comprises from 0.4 to 1.5 weight percent, and the aluminum base alloy furthermore comprises Mg in an amount from 0.2 to 1.0 weight percent of said alloy.

Claim 16

Dependent Claim 35 words

A method according to claim 14, wherein said aluminum-base alloy further contains at least one of Ag in an amount up to 0.8 weight percent and Zn in an amount up to 1.0 weight percent.

Claim 17

Dependent Claim 35 words

A method according to claim 13, wherein said aluminum-base alloy further contains at least one of Ag in an amount up to 0.8 weight percent and Zn in an amount up to 1.0 weight percent.

Claim 18

Dependent Claim 61 words

A method according to claim 1, wherein the yield strength of said alloy at cryogenic temperature is greater than its yield strength at room temperature, which is greater than 85 ksi (longitudinal), and the plane strain fracture toughness of said alloy at cryogenic temperature is greater than its plane strain fracture toughness at room temperature, which is greater than 25 ksi√in.

Claim 19

Dependent Claim 61 words

A method according to claim 13, wherein the yield strength of said alloy at cryogenic temperature is greater than its yield strength at room temperature, which is greater than 85 ksi (longitudinal), and the plane strain fracture toughness of said alloy at cryogenic temperature is greater than its plane strain fracture toughness at room temperature, which is greater than 25 ksi√in.

Claim 20

Dependent Claim 88 words

A wrought aluminum-base alloy consisting essentially of from 2.8 to 4.8 weight percent Cu, from 0.4 to 1.5 weight percent Li, from 0.2 to 1.0 weigth percent Mg, and the balance aluminum and incidental impurities, wherein said alloy is worked, artificially aged, or worked and artificially aged an amount sufficient to provide strength and fracture toughness to said alloy at cryogenic temperature substantially equal to or greater than the strength and fracture toughness at room temperature, wherein the fracture toughness at room temperature is a least 18.7 ksi√in.

Claim 21

Dependent Claim 88 words

A wrought aluminum-base alloy consisting essentially of from 2.8 to 4.8 weight percent Cu, from 0.4 to 1.5 weight percent Li, from 0.2 to 1.0 weigth percent Mg, and the balance aluminum and incidental impurities, wherein said alloy is worked, artificially aged, or worked and artificially aged an amount sufficient to provide strength and fracture toughness to said alloy at cryogenic temperature substantially equal to or greater than the strength and fracture toughness at room temperature, wherein the fracture toughness at room temperature is a least 18.7 ksi√in.

Claim 22

Dependent Claim 43 words

A wrought aluminum-base alloy according to claim 19, wherein said alloy further contains from 0.01 to 1.0 weight percent of at least one grain refiner selected from the group consisting of Zr, Ti, Cr, Mn, Hf, Nb, B, V, and TiB 2 .

Claim 23

Dependent Claim 38 words

A wrought aluminum-base alloy according to claim 20, wherein said aluminum-base alloy further contains at least one of Ag in an amount up to 0.8 weight percent and Zn in an amount of up to 1.0 weight percent.

Claim 24

Dependent Claim 68 words

A wrought aluminum-base alloy according to claim 20, wherein said Cu comprises from 3.0 to 4.5 weight percent, said Li comprises from 0.7 to 1.1 weight percent, said Mg comprises from about 0.3 to about 0.6 weight percent, and said grain refiner comprises from 0.08 to 0.3 weight percent of said alloy, wherein said grain refiner is selected from the group consisting of Zr, Ti and combinations thereof.

Claim 25

Dependent Claim 68 words

A wrought aluminum-base alloy according to claim 21, wherein said Cu comprises from 3.0 to 4.5 weight percent, said Li comprises from 0.7 to 1.1 weight percent, said Mg comprises from about 0.3 to about 0.6 weight percent, and said grain refiner comprises from 0.08 to 0.3 weight percent of said alloy, wherein said grain refiner is selected from the group consisting of Zr, Ti, and combinations thereof.

Claim 26

Dependent Claim 23 words

A wrought aluminum-base alloy according to claim 20, wherein said Cu comprises from about 3.0 to about 4.5 weight percent of said alloy.

Claim 27

Dependent Claim 23 words

A wrought aluminum-base alloy according to claim 20, wherein said Li comprises from about 0.7 to about 1.1 weight percent of said alloy.

Claim 28

Dependent Claim 18 words

A wrought aluminum-base alloy according to claim 20, wherein said alloy is in the form of an extrusion.

Claim 29

Dependent Claim 18 words

A wrought aluminum-base alloy according to claim 20, wherein said alloy is in the form of a plate.

Claim 30

Dependent Claim 18 words

A wrought aluminum-base alloy according to claim 20, wherein said alloy is in the form of a sheet.

Claim 31

Dependent Claim 65 words

A wrought aluminum-base alloy according to claim 20, wherein the yield strength of said alloy at cryogenic temperature is substantially equal to greater than its yield strength at room temperature, which is greater than 85 ksi, and the plane strain fracture toughness of said alloy at cryogenic temperature is greater than its plane strain fracture toughness at room temperature, which is greater than 25 ksi√in.

Claim 32

Dependent Claim 62 words

A wrought aluminum-base alloy according to claim 20, wherein the yield strength of said alloy at cryogenic temperature is greater than its yield strength at room temperature, which is greater than 85 ksi, and the plane stress fracture toughness of said alloy at cryogenic temperature is greater than its plane stress fracture toughness at room temperature, which is greater than 25 ksi√in.

Claim 33

Dependent Claim 33 words

A wrought aluminum-base alloy according to claim 20, wherein said alloy is underaged to a yield strength at least 5 ksi below the peak yield strength that said alloy is capable of attaining.

Claim 34

Dependent Claim 104 words

A cryogenic material-holding container made from an alloy consisting essentially of from 2.8 to 4.5 weight percent Cu, from 0.4 to 1.5 weight percent Li, from 0.2 to 1.0 weight percent Mg, and the balance aluminum and incidental impurities, wherein said alloy is worked, artificially aged, or worked and artificially aged an amount sufficient to provide strength and fracture toughness to said alloy at cryogenic temperature substantially equal to or greater than the strength and fracture toughness at room temperature, wherein the fracture toughness at room temperature is at least 18.7 ksi√in and the fracture toughness at -196° C. is at least 19.2 ksi√in.

Claim 35

Dependent Claim 104 words

A cryogenic material-holding container made from an alloy consisting essentially of from 2.8 to 4.5 weight percent Cu, from 0.4 to 1.5 weight percent Li, from 0.2 to 1.0 weight percent Mg, and the balance aluminum and incidental impurities, wherein said alloy is worked, artificially aged, or worked and artificially aged an amount sufficient to provide strength and fracture toughness to said alloy at cryogenic temperature substantially equal to or greater than the strength and fracture toughness at room temperature, wherein the fracture toughness at room temperature is at least 18.7 ksi√in and the fracture toughness at -196° C. is at least 19.2 ksi√in.

Claim 36

Dependent Claim 43 words

A cryogenic material-holding container according to claim 32, wherein said alloy further contains from 0.01 to 1.0 weight percent of at least one grain refiner selected from the group consisting of Zr, Ti, Cr, Mn, Hf, Nb, B, V, and TiB 2 .

Claim 37

Dependent Claim 38 words

A cryogenic material-holding container according to claim 33, wherein said aluminum-base alloy further contains at least one of Ag in an amount up to 0.8 weight percent and Zn in an amount of up to 1.0 weight percent.

Claim 38

Dependent Claim 63 words

A cryogenic material-holding container according to claim 33, wherein the yield strength of said alloy at cryogenic temperature is greater than its yield strength at room temperature, which is greater than 85 ksi (longitudinal), and the plane strain fracture toughness of said alloy at cryogenic temperature is greater than its plane strain fracture toughness at room temperature, which is greater than 25 ksi√in.

Claim 39

Dependent Claim 63 words

A cryogenic material-holding container according to claim 33, wherein the yield strength of said alloy at cryogenic temperature is greater than its yield strength at room temperature, which is greater than 85 ksi (longitudinal), and the plane stress fracture toughness of said alloy at cryogenic temperature is greater than its plane stress fracture toughness at room temperature, which is greater than 25 ksi√in.

Claim 40

Dependent Claim 34 words

A cryogenic material-holding container according to claim 33, wherein said alloy is underaged to a yield strength at least about 5 ksi below the peak yield strength that said alloy is capable of attaining.

Claim 41

Dependent Claim 16 words

A cryogenic material-holding container according to claim 33, wherein said container has been formed by welding.

Claim 42

Dependent Claim 26 words

A cryogenic material-holding container according to claim 33, wherein said cryogenic material is selected from the group consisting of liquid hydrogen, liquid oxygen, and liquid nitrogen.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1998-10-02	1999-04-03	1999-10-03	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2002-10-02	2003-04-03	2003-10-03	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2006-10-02	2007-04-03	2007-10-03	$7700.00	Window Closed / Lapsed

Al-Cu-Li alloys with improved cryogenic fracture toughness

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