A STUDY OF THE POSSIBILITY OF REINFORCING HIGH-TEMPERATURE ALLOYS BY ADDITION OF REFRACTORY POWDERS. Period covered: April 1956 to July 1957
The reinforcement of 80 Ni-20 Cr alloy by the addition of such refractory oxides as TiO/sub 2/ and Al/sub 2/O/sub 3/ was attempted. Several powder metallurgical fabrication techniques were investigated such as (1) pressing and sintering, (2) pressing and sintering followed by various working procedures, (3) internal oxidation and (4) liquid phase sintering. ln the press- sinter method of fabrication, the best stressrupture characteristics of 1600 deg F were obtained with additions of 3.0 to 4.5% TiO/sub 2/. An addition of 4.5% TiO/sub 2/ resulted in a rupture time of 29.6 hours as compared to a rupture time of 1.0 hour obtained on bars containing no TiO/sub 2/. Various hot and coid working procedures did not result in any improved stress-rupture properties. The liquid phase sintering technique produced the best stress-rupture properties. Stress-rupture tests at 1800 deg F showed a stress of 6200 psi for an 80 Ni-20 Cr + 1.0% TiO/sub 2/ + C material which was more than three fold better than wrought Nichrome V. Stress-rupture tests on the same materials at 1975 deg F showed the liquid phase material to have twice the strength of Nichrome V. The impact strengths varied from 10 to more than 50 inch pounds. Room temperature tensiie strengths which were fairly consistent, averaged about 75,000 psi. The thermal shock properties were excellent and the oxidation resistance, although not quite as high as Nichrome V, was considered good. (For preceding period see WADC-TR-56- 190.) (M.H.R.)
- Research Organization:
- Mallory (P.R.) and Co., Inc. Metallurgical Research Lab., Indianapolis
- DOE Contract Number:
- AF33(616)-2959
- NSA Number:
- NSA-12-008417
- OSTI ID:
- 4350059
- Report Number(s):
- WADC-TR-57-535; AD-150971
- Resource Relation:
- Other Information: Project title: CERAMIC AND CERMET MATERIALS. Task title: CERAMIC AND CERMET MATERIALS DEVELOPMENT. Orig. Receipt Date: 31-DEC-58
- Country of Publication:
- United States
- Language:
- English
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