Two prototype laminar composites have shown potential for high strength and high temperature applications. These composites might be made with less in-place anisotropy and be less expensive than comparable fiber composites

Hoffman, C. A.

Weeton, J. W.

English

NASA Technical Reports Server

February 1973
	 B73-10068 
•	 NASA TECH BRIEF	
c Lewis Research Center 
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 National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Metal-Metal Reinforced Laminar Composites 
Laminar composites consisting of alternate layers of 
metal sheet or foil, diffusion bonded together, have 
demonstrated a potential for high strength at high 
temperatures. In terms of the strength of the constitu-
ents, this potential is comparable to that of fiber rein-
forced composites. Many combinations of laminated ma-
terials can be envisioned that could be advantageously 
fabricated into parts or components of structures. 
The potential of laminar composites can be illus-
trated by the properties of two recently developed 
prototype systems: 
The first prototype consisted of laminae of the 
oxidation resistant alloy Nichrome V alternated with 
tungsten (the reinforcing or stronger phase). These 
composites contained nominally 50 volume percent of 
each material as foil or sheets of 0.025, 0.125, or 0.50 
mm (0.001, 0.005 or 0.020 inch) thickness At test 
temperatures of 1144 K (16000 F) and under all 
test conditions, these composites had strengths equal 
to or considerably above the values calculated for 
them using rule-of-mixtures equations, based on the 
individual strengths of the tungsten and Nichrorne V. 
At 1366 K (2000 F) for most short-time test conditions 
(less than 10 hours), the composites had strengths above 
the calculated "rule-of-mixtures" strengths. For 100 hour 
life, the strength of the thickest (0.5 mm-0.020 inch) lami-
nae composite equaled the "rule-of-mixtures" strength. 
The second prototype consisted of a laminar com-
posite of 77 volume percent W-Re-Hf-C alloy sheet 
alternated with 23 volume percent Inconel 600 foil. 
This composite had a 1366 K (2000° F) tensile strength 
of 6.83 x 108 N/rn2 (99,000 psi) and an extrapolated 
100 hour stress-rupture strength of about 3.4 x 108 
N/rn 2 (50,000 psi). These values compare favorably 
with some fiber composite materials which have been 
developed.
These two prototype composites have demonstrated 
that laminar metal-metal composites have a potential 
for high strength and high temperature applications 
similar to that demonstrated for metal-fiber-metal matrix 
composites. These two composites, intended as demon-
stration prototypes, were made from available materials 
rather than materials specifically selected for maximum 
performance as laminar composites; the results, how-
ever, indicate that practical high-performance laminar 
composites can probably be designed. The results also 
indicate that the development of stronger reinforcing 
laminae designed specifically for laminar composite use 
could result in even higher strength composites. 
Because laminar composites have several valuable 
intrinsic characteristics, they may be more desirable for 
certain applications than fiber composites. For example, 
they probably can be made with less in-plane anisotropy 
than fiber composites without sacrificing maximum 
strength or modulus. Less in-plane anisotropy should 
enable laminar composites to withstand high transient 
stresses arising from impact, fatigue, etc., while pro-
viding a higher safety factor. Generally, too it is be-
lieved that laminar composites may be less expensive 
to produce than comparable fiber composites. 
Applications for laminar composites are numerous. 
Laminar composites can be designed or "tailor made" 
for specific applications, and to have specific properties 
such as corrosion resistance, strength, modulus, high-
temperature strength, impact resistance, and ease of 
fabrication. One of the most promising potential uses 
for laminar composites, compared to bulk materials or 
fiber composites, is in high-speed, high-temperature 
turbines. For example, disks for the multiple turbine 
and compressor stages may possibly be made with 
laminated materials. Other aerospace applications might 
(continued overleaf) 
This document was prepared under the sponsorship of the National
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Aeronautics and Space Administration. Neither the United States 	 information contained in this document, or warrants that such use 
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.
https://ntrs.nasa.gov/search.jsp?R=19730000068 2020-03-17T06:39:41+00:00Z
include high-temperature turbine blades, vanes, com-
bustion chambers, high-pressure chambers for high-
temperature use (e.g., in advanced rocket engines), 
thrust reversers, re-entry vehicle edges, high-temperature 
structural panels and stiffeners. Also, furnace supports, 
furnace or metallurgical hearths, and nuclear furnace 
components could be made from laminar composites. 
The laminar approach could also be extended to include 
composites incorporating ceramics, plastics, and various 
combinations of these materials and metals. 
Note: 
Documentation may be obtained from: 
Technology Utilization Officer 
Lewis Research Center 
21000 Brookpark Road 
Cleveland, Ohio 44135 
Reference: B73-10068
Patent status: 
Inquiries concerning rights for the commercial use 
of this invention should be addressed to: 
NASA Patent Counsel 
Mail Stop 500-311 
Lewis Research Center 
21000 Brookpark Road 
Cleveland, Ohio 44135 
Source: J. W. Weeton and C. A. Hoffman

Lewis Research Center

(LEW-1 1790)
SB73-10068	 Category 04 


Metal-metal reinforced laminar composites

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