Heat treatment for nickel-base superalloys

• US 5,100,484 A
• Filed: 01/26/1990
• Issued: 03/31/1992
• Est. Priority Date: 10/15/1985
• Status: Expired due to Term

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Darolia, Ramgopal, Buchakjian, Leo Jr., Wukusick, Carl S.
• Primary Examiner(s): Dean, R.
• Assistant Examiner(s): Phipps, Margery S.
• Application Number:
  US07/472,420
• Time in Patent Office: 795 Days
• Field of Search: 148/20.3, 148/162, 148/410, 148/404, 420/448
• US Class Current: 148/562
• CPC Class Codes: C22F 1/10 of nickel or cobalt or alloys based thereon

Abstract

The present invention is directed to a heat treatment for nickel-base superalloys used to make single crystal parts and components for gas turbine engines. The heat treatment is conducted in a vacuum or inert atmosphere and includes the steps of solutionizing in a temperature range sufficient to achieve solution of at least 95% of the γ'"'"' phase, preferably 2385°-2395° F., for 2 hours; cooling to 2000° F. at 100° F./min minimum, furnace cooling to 1200° F. in 60 min. or less and thereafter cooling to room temperature; heating to 2050°±25° F. for 4 hours; furnace cooling to below 1200° F. in 6 min. or less and thereafter to room temperature; and heating to 1650°±25° F. for 4 hours and thereafter furnace cooling to room temperature.

Claims

1. A heat treatment process conducted in a vacuum or inert atmosphere comprising the steps of:

a) selecting a single crystal article having a composition consisting essentially of, in percentages by weight, 5-10 Cr, 5-10 Co, 0-2 Mo, 3-10 W, 3-8 Ta, 0-2 Ti, 5-7 Al, 0-6 Re, 0-0.5 Hf, 0-0.07 C, 0-0.015 B, and 0-0.075 Y, the balance being nickel and incidental impurities;

b) heating for 2 hours in a temperature range sufficient to achieve solutioning of at least about 95% of the γ

'"'"' phase;

c) cooling to 2000°

F. at 100°

F./minute minimum and then to 1200°

F. in about 60 minutes;

d) heating to 2050°

±

25°

F. for 4 hours;

e) cooling to below 1200°

F. in 6 minutes or less; and

f) heating to 1650°

±

25°

F. for 4 hours.

2. The heat treatment of claim 12 wherein the temperature range in b) is from about 2385°

to 2395°

F.

3. A heat treatment process conducted in a vacuum or inert atmosphere comprising the steps of:

a) selecting a single crystal article having a composition consisting essentially of, in percentages by weight, 6.75-7.25 Cr, 7.0-8.0 Co, 1.3-1.7 Mo, 4.75-5.25 W, 6.3-6.7 Ta, 0.02 max. Ti, 6.1-6.3 Al, 2.75-3.25 Re, 0.12-0.18 Hf, 0.04-0.06 C, 0.003-0.005 B, and 0.005-0.030 Y, the balance being nickel and incidental impurities;

b) heating for 2 hours in a temperature range sufficient to achieve solutioning of at least about 95% of the γ

'"'"' phase;

c) cooling to 2000°

F. at 100°

F./minute minimum and then to 1200°

F. in about 60 minutes;

d) heating to 2050°

±

25°

F. for 4 hours;

e) cooling to below 1200°

F. in 6 minutes or less; and

f) heating to 1650°

±

25°

F. for 4 hours.

4. The heat treatment of claim 3 wherein the temperature range in b) is from about 2385°

to 2395°

F.

5. The heat treatment of claim 3 wherein the composition of the article consists essentially of, in percentages by weight, 7 Cr, 7.5 Co, 1.5 Mo, 5 W, 6.5 Ta, 0 Ti, 6.2 Al, 3 Re, 0.15 Hf, 0.05 C, 0.004 B, and 0.01 Y, the balance being nickel and incidental impurities.