Ductile tungsten-nickel alloy and method for making same
Process for fabricating articles of tungsten-nickel-iron alloy
Tungsten-nickel-cobalt alloy and method of producing same
Ductile tungsten-nickel-alloy and method for manufacturing same
Process for producing molybdenum and tungsten alloys containing metal carbides
Sintering process Patent #: 4698096
ApplicationNo. 07/081779 filed on 08/05/1987
US Classes:419/23, Powder shape or size characteristics419/29, Subsequent heat treatment (e.g., annealing, etc.)419/46, Alloying occurs during sintering419/47, Liquid phase sintering419/53, Plural heating steps including sintering419/54, Different temperatures419/58, Hydrogen or hydrogen plus nitrogen (Nitrogen per se in 57)75/248Base metal confined to Tungsten(W)
ExaminersPrimary: Lechert, Stephen J. Jr.
Attorney, Agent or Firm
International ClassesB22F 3/12 (20060101)
C22C 1/04 (20060101)
AbstractA process is disclosed for producing tungsten heavy alloy billets. The process involves forming a uniform blend of elemental powders to form a tungsten alloy having a tungsten content of equal to or less than about 91% by weight and wherein the particle size of the tungsten is no less than about 2 micrometers in diameter. This blend is uniformly packed into a container having thermal expansion similar to that of the powder. The blend is then sintered in a hydrogen atmosphere at a temperature sufficient to impart strength to the powder and to reduce oxides and remove volatile impurities from the powder without significant densification in the powder. The powder is then solid state sintered in a reducing atmosphere at a sufficient temperature to densify the powder to at least about 90% of the theoretical density but at a temperature below the liquid phase sintering temperature of the powder, to form the billet. If the tungsten content of the alloy is greater than about 88% by weight, the solid state sintered powder can then be liquid state sintered by slowly raising the temperature from the solid state sintering temperature to the liquid phase sintering temperature and holding at this temperature for a sufficient time to accomplish the liquid sintering and achieve a density of greater than about 99% of the theoretical density in the billet.