Dispersion strengthened mechanically alloyed Al-Mg-Li

Claim 2

A process for producing a dispersion strengthened aluminum-base alloy comprising: (a) providing a mechanically alloyed dispersion strengthened powder consisting essentially, by weight, of about 0.5% to about 4% lithium, above 1% up to about 5% magnesium, a small but effective amount for increased strength up to about 2% carbon, a small but effective amount for thermal stability up to 1% oxygen, and the balance, essentially aluminum, the dispersoid content of the alloy being present up to about 8 volume %; (b) degassing and consolidating the mechanically alloyed powder at a temperature in the range of about 480° C. to a temperature below incipient liquification; (c) solution treating the consolidated alloy at a temperature of about 425° C. to about 570° C., whereby the alloy in the solution treated condition has a YS of at least 414 MPa, elongation of at least about 7%, and fracture toughness (K Q ) at 22 mm B of at least about 16.5 MPa √m.

Claim 3

A process of claim 1, wherein the solution treated alloy is subjected to an aging treatment to below peak strength.

Claim 4

A process of claim 1, wherein degassing is effected at a temperature between about 510° C. to about 540° C.

Claim 5

A process of claim 1, wherein solution treatment is effected at about 480° C. to about 520° C. for a period of about 1 to 4 hours.

Claim 6

A process of claim 1, wherein aging treatment is effected at about 120° C. to 210° C. for about 1 hour to 10 hours.

Claim 7

A process of claim 1, wherein in the degassed, consolidated alloy the lithium content is above 1.5% and the oxygen content does not exceed about 0.5%.

Claim 8

A process of claim 6, wherein the oxygen content of the degassed, consolidated alloy is about 0.2 to about 0.4%.

Claim 9

A process of claim 6, wherein the oxygen content of the degassed, consolidated alloy is less than 0.4%.

Claim 10

A process of claim 1, wherein the lithium content of the degassed, consolidated alloy is about 1% to about 3%.

Claim 11

A process of claim 1, wherein the lithium content of the degassed, consolidated alloy is about 1.5% to about 2.5%.

Claim 12

A process of claim 1, wherein the magnesium content of the degassed, consolidated alloy is about 2% to about 4.5%.

Claim 13

A process of claim 1, wherein the carbon content of the degassed, consolidated alloy is about 0.5% to about 2%.

Claim 14

A process of claim 1, wherein the carbon content of the degassed, consolidated alloy is about 0.8% to about 1.2%.

Claim 15

A mechanically alloyed dispersion strengthened aluminum base alloy produced by the method of claim 1.

Claim 16

A mechanically alloyed dispersion strengthened aluminum-base alloy in the solution treated and underaged condition consisting essentially of about 1.5 to about 2.5% lithium, about 2% up to about 4.5% magnesium, about 0.7 to about 1.2% carbon and a small but effective amount for increased stability up to 1% oxygen.

Claim 17

A mechanically alloyed dispersion strengthened aluminum-base alloy in the solution treated and underaged condition consisting essentially of about 1.5 to about 2.5% lithium, about 2% up to about 4.5% magnesium, about 0.7 to about 1.2% carbon and a small but effective amount for increased stability up to 1% oxygen.

Claim 18

An alloy of claim 15, wherein the oxygen content is less than 0.5%.

Claim 19

An alloy of claim 15, wherein the oxygen content is between about 0.2% and about 0.4%.

Claim 20

An alloy of claim 15, wherein the ratio of carbon to oxygen is at least 2 to 1.

Claim 21

An alloy of claim 15, wherein the ratio of carbon to oxygen is greater than about 2.5 to 1.

Claim 22

A mechanically alloyed dispersion strengthened aluminum-base alloy in the solution treated condition consisting essentially of about 1.5 to about 2.5% lithium, about 2% up to about 4.5% magnesium, about 0.7 to about 1.2% carbon and a small but effective amount for increased stability up to 1% oxygen.

Claim 23

A mechanically alloyed dispersion strengthened aluminum-base alloy in the solution treated condition consisting essentially of about 1.5 to about 2.5% lithium, about 2% up to about 4.5% magnesium, about 0.7 to about 1.2% carbon and a small but effective amount for increased stability up to 1% oxygen.

Claim 24

An alloy of claim 20, wherein the oxygen content is less than 0.5%.

Claim 25

An alloy of claim 20, wherein the oxygen content is between about 0.2% and about 0.4%.

Claim 26

An alloy of claim 20, wherein the ratio of carbon to oxygen is at least 2 to 1.

Claim 27

An alloy of claim 20, wherein the ratio of carbon to oxygen is at least 2.5 to 1.

Claim 28

A process for producing a dispersion strengthened aluminum-base alloy comprising: (a) providing a mechanically alloyed dispersion strengthened powder consisting essentially, by weight, of about 0.5% to about 4% lithium, above 1% up to about 5% magnesium, a small but effective amount for increased strength up to about 2% carbon, a small but effective amount for thermal stability up to 1% oxygen, and the balance, essentially aluminum, the dispersoid content of the alloy being present up to about 8 volume %; (b) degassing and consolidating the mechanically alloyed powder at a temperature in the range of about 480° C. to a temperature below incipient liquification; and degassed and consolidated alloy having a carbon level exceeding the oxygen level and (c) solution treating the consolidated alloy at a temperature of about 425° C. to about 570° C., whereby the alloy in the solution treated condition has a YS of at least 414 MPa, elongation of at least about 7%, and fracture toughness (K Q ) at 22 mm B of at least about 16.5 MPa, √m.

Claim 29

A process for producing a dispersion strengthened aluminum-base alloy comprising: (a) providing a mechanically alloyed dispersion strengthened powder consisting essentially, by weight, of about 0.5% to about 4% lithium, above 1% up to about 5% magnesium, a small but effective amount for increased strength up to about 2% carbon, a small but effective amount for thermal stability up to 1% oxygen, and the balance, essentially aluminum, the dispersoid content of the alloy being present up to about 8 volume %; (b) degassing and consolidating the mechanically alloyed powder at a temperature in the range of about 480° C. to a temperature below incipient liquification; and degassed and consolidated alloy having a carbon level exceeding the oxygen level and (c) solution treating the consolidated alloy at a temperature of about 425° C. to about 570° C., whereby the alloy in the solution treated condition has a YS of at least 414 MPa, elongation of at least about 7%, and fracture toughness (K Q ) at 22 mm B of at least about 16.5 MPa, √m.

Claim 30

A process of claim 25, wherein the oxygen content of the degassed, consolidated alloy does not exceed about 0.5%.

Claim 31

A process of claim 25, wherein the oxygen content of the degassed, consolidated alloy is about 0.2% to about 0.4%.

Claim 32

A process of claim 25, wherein the carbon content of the degassed, consolidated alloy is about 0.5% to about 2%.

Claim 33

A process of claim 25, wherein the magnesium content of the degassed, consolidated alloy is about 2% to about 4.5%.

Claim 34

A mechanically alloyed dispersion strengthened aluminum-base alloy consisting essentially of about 1.5% to about 2.5% lithium, about 2% up to about 4.5% magnesium, about 0.7% up to about 1.2% carbon, a small but effective amount for increased stability up to about 1% oxygen, said carbon level exceeding the oxygen level and said alloy having in the solution treated condition a YS of at least 414 MPa, elongation of at least about 7%, and fracture toughness (K Q ) at 22 mm B of at least about 16.5 MPa √m.

Claim 35

A mechanically alloyed dispersion strengthened aluminum-base alloy consisting essentially of about 1.5% to about 2.5% lithium, about 2% up to about 4.5% magnesium, about 0.7% up to about 1.2% carbon, a small but effective amount for increased stability up to about 1% oxygen, said carbon level exceeding the oxygen level and said alloy having in the solution treated condition a YS of at least 414 MPa, elongation of at least about 7%, and fracture toughness (K Q ) at 22 mm B of at least about 16.5 MPa √m.