Abstract: A method is provided for obtaining an alloy having an ordered microstructure which comprises the steps of heating the central portion of the alloy under uniform temperature so that it enters a liquid phase while the outer portions remain solid, applying a constant electric current through the alloy during the heating step, and solidifying the liquid central portion of the alloy by subjecting it to a temperature-gradient zone so that cooling occurs in a directional manner and at a given rate of speed while maintaining the application of the constant electric current through the alloy. The method is particularly suitable for use with nickel-based superalloys. The method of the present invention produces an alloy having superior characteristics such as reduced segregation. After subsequent precipitation by heat-treatment, the alloys produced by the present invention will have excellent strength and high-temperature resistance.
Type:
Grant
Filed:
May 31, 1990
Date of Patent:
January 14, 1992
Assignee:
The United States of America as represented by the Administrator of the National Aeornautics and Space Administration
Inventors:
Eugene C. McKannan, Deborah D. Schmidt, Shaffiq Ahmed, Robert W. Bond