Classifications

• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C27/00—Alloys based on rhenium or a refractory metal not mentioned in groups C22C14/00 or C22C16/00
  • C22C27/04—Alloys based on tungsten or molybdenum
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C1/00—Making non-ferrous alloys
  • C22C1/04—Making non-ferrous alloys by powder metallurgy
  • C22C1/045—Alloys based on refractory metals

Definitions

• ABSTRACT OF THE DISCLOSURE A wrought tungsten-base alloy containing up to 1.0 weight percent rhenium and between 1 and 35 parts per million manganese. The alloy exhibits a low ductile-tobrittle transition temperature and substantially the same strength and high temperature properties as unalloyed tungsten.
• This invention relates to tungsten-base alloys characterized by ductile-to-brittle transition temperatures which arev at or below room temperature.
• the alloy should be at least as strong and have a recrystallization temperature which is not less than that of unalloyed tungsten.
• tungsten-base alloy which employs less than 1% rhenium and yet has a low ductile-to-brittle transition temperature.
• Another object is to provide a tungsten-base alloy which is ductile at room temperature yet has substantially the same strength and high temperature properties as unalloyed tungsten.
• tungsten-base alloys are produced by blending less than 1% rhenium powder and be tween 0.1% and 0.3% manganese power with tungsten tungsten power. (All percentages given are by Weight of tungsten.)
• the blend is hydrostatically pressed at about 50,000 pounds per square inch to form a billet after it is presintered at about 1300 C. for approximately 4 hours in vacuo at a pressure of about 2X10" torr. Following the 1300 C. presintering, the blend is again presintered in vacuo at 1650 C. for an additional 4 hours.
• the 1300 C. presinter permits the manganese to combine with the residual oxygen in the blend to form manganese di oxide and the 1650 C. presinter volatilizes part of the manganese dioxide and much of the residual manganese.
• a flowing atmosphere of hydrogen or an inert gas may be used in place of vacuum presintering.
• the rate of gas flow should be sufficient to remove both the manganese and manganese dioxide vapors so that their vapor pressure at the billet is less than the normal vapor pressure of these elements at the sintering temperature.
• the blend is sintered at about 2350" C. for 6 hours under the same atmospheric conditions as was used in the presintering steps.
• the alloy is densified and almost all of the remaining oxygen combined with the manganese and removed as manganese dioxide.
• the alloy is rolled to desired thickness and cleaned.
• ductile-to-brittle transition temperatures were carried out for a number of compositions by attempting to bend at several temperatures specimens 1 inch long by inch wide by 0.04 inch thick over a radius four times the thickness of the specimen through a angle.
• the minimum temperature at which the sample cracked after a small but perceptible amount of bending was measured as was the minimum temperature at which the sample bent 105 without cracking (ductility temperature).
• Alloy sheet 0.04 inch thick was fabricated in the manner previously described by blending element a1 manganese, rhenium and tungsten in the percentages given in the following table. Samples were tested for ductile-brittle transi tion temperatures, oxygen content, tensile strength and recrystallization temperature.
• the amount of manganese in the final alloys analyzed with the mass spectrometer was between'one and 13 parts per million. Also, the percentage of rhenium in the final alloy was found by emission spectroscopy to be substantially unchanged from that employed in the initial blend.
• a sintered alloy characterized by high strength at elevated temperatures and a low ductile-to-brittle transition temperature in the range C. to +35 C. consisting essentially of up to 1 weight percent rhenium, between 1 and 35 parts per million manganese, and the balance tungsten.
• a sintered alloy characterized by high strength at elevated temperatures and a low ductile-to-brittle transition temperature in the range 5 C. to +35 C. consisting essentially of not more than 1 weight percent rheninm, at least 1 part per million manganese, and the balance tungsten.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Powder Metallurgy (AREA)

Priority Applications (9)

Applications Claiming Priority (1)

Publications (1)

Family

ID=23771308

Family Applications (1)

Country Status (8)

Cited By (3)

Citations (6)

• 1965
  • 1965-04-06 US US446097A patent/US3359082A/en not_active Expired - Lifetime
• 1966
  • 1966-04-04 AT AT318766A patent/AT265677B/de active
  • 1966-04-05 NL NL6604566A patent/NL6604566A/xx unknown
  • 1966-04-05 CH CH495766A patent/CH454469A/fr unknown
  • 1966-04-05 ES ES0325156A patent/ES325156A1/es not_active Expired
  • 1966-04-06 JP JP41021382A patent/JPS4839124B1/ja active Pending
  • 1966-04-06 BE BE679139D patent/BE679139A/xx unknown
  • 1966-04-06 DE DE19661533347 patent/DE1533347B1/de active Pending

Patent Citations (6)

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