High-temperature Tensile and Stress-rupture Properties of Some Alloys in the Tungsten-molybdenum System PDF Download

Author: M. Semchyshen
Publisher:
ISBN:
Category :
Languages : en
Pages : 101

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Book Description
Solid-solution-strengthened tungsten-base alloys were vacuum-arc-cast with relatively large additions of tantalum, Columbium, and/or molybdenum. Machined blanks from the ingots were extruded to round bar stock at temperatures from 3600 to 4000 F. Extrusion recoveries varied considerably from heat-to-heat. Elevated-temperature tensile tests were performed on specimens machined from available extruded bar stock. Strengths were well above those reported for unalloyed tungsten, but were below those resulting from earlier studies on dispersion-strengthened tungsten-base alloys. Molybdenum-base alloy sheets were prepared representing two compositions and three thermomechanical histories. Compositions studied were Mo + 1.25% Ti + 0.3% Zr + 0.1% C (TZC), and Mo + 0.3% Zr + 0.03% C. The thermomechanical variables imposed were solution heat treatments at various stages during the working schedules. Recrystallization behavior, bend transition temperatures, and tensile properties were quite sensitive to working schedules. Earlier work at this Laboratory indicated that in-process solution treatments at temperatures sufficiently high to effect increases in tensile strength usually resulted in increased transition temperatures. The present work has shown that a much more favorable trade-off between strength and transition temperature can result from the proper placement of the solution treatment in the working schedule.

Author: M. Semchyshen
Publisher:
ISBN:
Category : Materials at high pressures
Languages : en
Pages : 86

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Book Description
A number of complex molybdenum-, molybdenumtungsten-, and tungsten-base alloys were consolidated by the vacuum-arc-casting technique. Successful extrusions were realized from all of the vacuum-arc-cast ingots. Extrusion constants well above those of earlier experiments were measured, indicative of the good elevated-temperature strength and concomitant high resistance to extrusion of the materials studied. Rolled bars were studied from the standpoint of recrystallization behavior, transition temperature, tensile properties as a function of temperature and, to a limited extent, creep-rupture properties. A carbon synergism was studied in the alloys Mo + 3% Ti + 0.5% Zr and Mo + 25% W + 1.25% Ti + 0.1% Zr from the standpoint of elevated temperature strength. In the case of both alloys, the carbon contents yielding the highest elevated temperature strengths also resulted in the highest transition temperatures as measured by the tensile test. An alloy based on Mo-50% W, and containing 0.8% Ti and 0.3% Zr, displayed exceptionally high strengths at elevated temperatures. The tensile transition temperature of this material was, however, above room temperature. (Author).

Author:
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ISBN:
Category :
Languages : en
Pages :

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Substantial increases in the high-temperature creep strength of Mo-Hf alloys can be obtained by internal nitriding. The creep resistance of internally nitrided Mo-1.86 wt % Hf is more than 100 times greater than that of other commercially available molybdenum-base alloys. The HfN precipitates appear to be stable over long times at temperatures near 1600 K. Internally nitrided Mo-Hf alloys appear to be good candidates for fabrication of components of space power systems where the ratio of high-temperature strength to weight is important. They are particularly good candidates for components that can be fabricated from the lower-strength unnitrided alloy and subsequently nitrided to provide high-temperature strength.

Author: E. J. Rapperport
Publisher:
ISBN:
Category : Alloys
Languages : en
Pages : 80

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Author: North Atlantic Treaty Organization. Advisory Group for Aeronautical Research and Development
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ISBN:
Category : Confrences
Languages : en
Pages : 612

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Author: J. A. Houck
Publisher:
ISBN:
Category : Molybdenum alloys
Languages : en
Pages : 10

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Author: Paul F. Sikora
Publisher:
ISBN:
Category : Molybdenum alloys
Languages : en
Pages : 24

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Author: Armour Research Foundation (U.S.)
Publisher:
ISBN:
Category : Metallurgy
Languages : en
Pages : 52

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An envelope-type microstructure produced by liquid-phase sintering techniques has been used to develop ductile molybdenum-base alloys for sodium-cooled fast reactor application.

Author: J. L. Ratliff
Publisher:
ISBN:
Category : Research and development projects
Languages : en
Pages : 70

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Book Description
Government-sponsored tungsten research and development efforts encompass a broad rage of technological activities. Typifying the extreme limits of efforts since January, 1960, studies have ranged from preparation of unalloyed metal to development of high-integrity fabricated shapes of tungsten-base materials. Nine major areas outline the broad over-all effort, and each is summarized within this report by brief technical discussions of 104 separate studies on 79 research programs. Included are preparation of metal, consolidation, primary and secondary working, joining, fabrication and performance of rocket nozzles, oxidation and other high-temperature reactions, protective coatings, properties, and physical metallurgy.

Author: D. A. Roberts
Publisher:
ISBN:
Category : Stainless steel
Languages : en
Pages : 18

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Book Description
Research and development in the field of high-strength stainless steels appears to be directed along two principal paths: (1) the development of alloys with improved strength properties and (2) the accumulation of information on the properties and physical metallurgy of existing alloys so that they may be used more effectively. By and large, the development of new alloys is being carried out by the stainless-steel producers, while the accumulation of property data for the most part is being undertaken on Government contracts. (Author).