Cobalt-tungsten superalloy has improved stress rupture characteristics. Appropriate additions were made to this base alloy using microprobe analyses and a fractional factorial experiment

Wallace, J. F.

English

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NASA TECH BRIEF 
June 1970	 Brief 70-10058 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage commercial 
application. Tech .Briefs are available on a subscription basis from the Clearinghouse for Federal Scientific and Technical 
Information, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Division, NASA, Code UT, Washington, D.C. 20546, 
Directionally Solidified Superalloy 
Metallurgists and industries using metal alloys 
will be interested in a cast directionally solidified 
cobalt-tungsten superalloy with improved stress 
rupture characteristics. 
Screened, arc-melted, cast binary alloys were 
alloyed with selected modifying elements and invest-
ment cast into stress rupture test bar clusters. A 
resulting composition that showed good behavior and 
properties was Co-15W. Appropriate additions 
were made to this base alloy using microprobe analy-
ses and a fractional factorial experiment to aid in the 
selection of alloying elements. 
The composition of the resulting superalloy was 
85% Co-15W base, 10% Cr, 2% Zr, 2% Ti, and 1% C 
by weight. This yielded an approximate overall com-
position of 72.3% Co, 12.7% W, 10% Cr, 2% Zr, 2% 
Ti, and 1% C by weight. 
Stress rupture cast bars of this superalloy with a 
diameter of 0.250 inch and a gage length of 1.25 inch 
were cast conventionally and unidirectionally on a 
water-cooled, copper chill brock in a vacuum after 
vacuum melting. Stress rupture tests were carried 
out. The stress rupture properties of this modified 
Co-15W alloy in both the conventionally, and uni-
directionally cast form compared favorably with 
those of similar types of high quality cast superalloys.
Note: 
The following documentation may be obtained 
from:
Clearinghouse for Federal Scientific 
and Technical Information 
Springfield, Virginia 22151 
Single document price $3.00 
(or microfiche $0.65) 
Reference: NASA CR-89651 (N67-40235), 
Dependence of Stress Rupture and 
Superplasticity on Structure in Co-W 
Alloys 
NASA-CR-89650 (N67-39657), Effects 
of Ti, Zr, and C on Structure and Proper-
ties of a Co-35 W-3Cr-0. I  Alloy 
Patent status: 
Inquiries about obtaining rights for the commercial 
use of this invention may be made to NASA, Code 
GP, Washington, D.C. 20546.
Source: J. F. Wallace of
Case Western Reserve University 
under contract to

NASA Headquarters
(HQN- 10522) 
Category 04 
This document was prepared under the sponsorship of the National 	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States 	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United 'States
	 will be free from privately owned.rights.
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Directionally solidified superalloy

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