US4494987A — Precipitation hardening austenitic superalloys

Claim 1

Independent Claim 97 words

An iron base, gamma prime precipitation hardening austenitic superalloy having improved ductility characteristics after neutron irradiation in a fast breeder nuclear reactor, comprising an iron-nickel-chromium alloy including about 0.05-0.5 weight percent of a ductility enhancing agent selected from the group consisting of yttrium, hafnium and scandium, alone or in combination with each other, titanium and aluminum in amounts effective to produce gamma prime hardening during thermal aging outside of said fast breeder nuclear reactor and silicon in an amount effective through interaction with said ductility enhancing agent to enhance the post neutron irradiation ductility of said alloy.

Claim 2

Dependent Claim 97 words

An iron base, gamma prime precipitation hardening austenitic superalloy having improved ductility characteristics after neutron irradiation in a fast breeder nuclear reactor, comprising an iron-nickel-chromium alloy including about 0.05-0.5 weight percent of a ductility enhancing agent selected from the group consisting of yttrium, hafnium and scandium, alone or in combination with each other, titanium and aluminum in amounts effective to produce gamma prime hardening during thermal aging outside of said fast breeder nuclear reactor and silicon in an amount effective through interaction with said ductility enhancing agent to enhance the post neutron irradiation ductility of said alloy.

Claim 3

Dependent Claim 19 words

The superalloy according to claim 1 wherein silicon comprises about 0.5 to about 1.5 weight percent of said alloy.

Claim 4

Dependent Claim 15 words

The superalloy according to claim 1 or 2 wherein said ductility enhancing agent is yttrium.

Claim 5

Dependent Claim 15 words

The superalloy according to claim 1 wherein said alloy contains said gamma prime phase alloy.

Claim 6

Dependent Claim 14 words

The superalloy according to claim 2 wherein said alloy contains said gamma prime phase.

Claim 7

Dependent Claim 80 words

A gamma prime strengthened austenitic superalloy comprising: about 7-17 weight percent chromium; about 24-45 weight percent nickel; about 2-3.8 weight percent titanium; about 0.5-2.2 weight percent aluminum; about 0.8-3.5 weight percent molybdenum; about 0.5-1.5 weight percent silicon; about 0.03-0.06 weight percent carbon; about 0.05-0.5 weight percent of an element selected from the group consisting of yttrium, hafnium and scandium, alone or in combination with each other; and wherein iron is essentially the balance of said gamma prime strengthened austenitic superalloy.

Claim 8

Dependent Claim 80 words

A gamma prime strengthened austenitic superalloy comprising: about 7-17 weight percent chromium; about 24-45 weight percent nickel; about 2-3.8 weight percent titanium; about 0.5-2.2 weight percent aluminum; about 0.8-3.5 weight percent molybdenum; about 0.5-1.5 weight percent silicon; about 0.03-0.06 weight percent carbon; about 0.05-0.5 weight percent of an element selected from the group consisting of yttrium, hafnium and scandium, alone or in combination with each other; and wherein iron is essentially the balance of said gamma prime strengthened austenitic superalloy.

Claim 9

Dependent Claim 15 words

The superalloy according to claim 6 further comprising up to about 2 weight percent manganese.

Claim 10

Dependent Claim 37 words

The superalloy according to claim 6 wherein said superalloy has improved fast neutron irradiation swelling properties and wherein said element is selected from the group consisting of hafnium and yttrium, alone or in combination with each other.

Claim 11

Dependent Claim 20 words

A duct for fuel pins, wherein said duct is comprised of the superalloy according to claim 1, 2 or 6.

Claim 12

Dependent Claim 15 words

A fuel pin cladding comprised of the superalloy according to claim 1, 2 or 6.

Claim 13

Dependent Claim 39 words

The superalloy according to claim 4, 5 or 6 fabricated by the process comprising the steps of: solution treating said superalloy; later aging said superalloy; and subsequently placing said superalloy in said fast breeder reactor in an aged condition.

Claim 14

Dependent Claim 32 words

The superalloy according to claim 1 or 2 fabricated by the process comprising the step of: cold working said superalloy; and later placing said superalloy in pile in a cold worked condition.

Claim 15

Dependent Claim 34 words

The superalloy fabricated by the process according to claim 12 further comprising the step of: aging said superalloy after said cold working and prior to placing said superalloy in said fast breeder nuclear reactor.

Claim 16

Dependent Claim 111 words

A gamma prime precipitation hardening austenitic superalloy having the following nominal composition: about 25 weight percent Ni; about 7.5 weight percent Cr; about 1.0 weight percent Si; about 1.0 weight percent Mo; about 0.2 weight percent Mn; about 0.05 weight percent Zr; about 3.3 weight percent Ti; about 1.7 weight percent Al; about 0.05 weight percent C; about 0.005 weight percent B; about 0.2 weight percent of an agent for enhancing the post neutron irradiation ductility of said superalloy after neutron irradiation in a fast breeder reactor selected from the group consisting of Sc, Y, La, and Hf, alone or in combination with each other; and the balance being essentially Fe.

Claim 17

Dependent Claim 111 words

A gamma prime precipitation hardening austenitic superalloy having the following nominal composition: about 25 weight percent Ni; about 7.5 weight percent Cr; about 1.0 weight percent Si; about 1.0 weight percent Mo; about 0.2 weight percent Mn; about 0.05 weight percent Zr; about 3.3 weight percent Ti; about 1.7 weight percent Al; about 0.05 weight percent C; about 0.005 weight percent B; about 0.2 weight percent of an agent for enhancing the post neutron irradiation ductility of said superalloy after neutron irradiation in a fast breeder reactor selected from the group consisting of Sc, Y, La, and Hf, alone or in combination with each other; and the balance being essentially Fe.

Claim 18

Dependent Claim 25 words

The alloy according to claim 14 wherein said agent for enhancing post neutron irradiation ductility is selected from the group consisting of Y and Hf.

Claim 19

Dependent Claim 13 words

The superalloy according to claim 2 wherein said ductility enhancing agent is scandium.

Claim 20

Dependent Claim 13 words

The superalloy according to claim 2 wherein said ductility enhancing agent is hafnium.

Claim 21

Dependent Claim 11 words

The superalloy according to claim 6 wherein said element is yttrium.

Claim 22

Dependent Claim 17 words

The alloy according to claim 14 wherein said agent for enhancing post neutron irradiation ductility is Y.

Claim 23

Dependent Claim 21 words

The alloy according to claim 6 wherein said element is limited to a concentration of about 0.2 to 0.5 weight percent.

Claim 24

Dependent Claim 23 words

The alloy according to claim 1 wherein said ductility enhancing agent is limited to a concentration of about 0.2 to 0.5 weight percent.

Claim 25

Dependent Claim 23 words

The alloy according to claim 2 wherein said ductility enhancing agent is limited to a concentration of about 0.2 to 0.5 weight percent.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1988-01-22	1988-07-23	1989-01-22	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1992-01-22	1992-07-23	1993-01-22	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1996-01-22	1996-07-23	1997-01-22	$7700.00	Window Closed / Lapsed

Precipitation hardening austenitic superalloys

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