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Direct metal fabrication (DMF) using a carbon precursor to bind the "green form" part and catalyze a eutectic reducing element in a supersolidus liquid phase sintering (SLPS) process

  • US 5,932,055 A
  • Filed: 11/11/1997
  • Issued: 08/03/1999
  • Est. Priority Date: 11/11/1997
  • Status: Expired due to Term
First Claim
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1. A method of direct metal fabrication (DMF) of metal parts, comprising:

  • using a carbon precursor to wet a metal powder alloy (X) whose particles are mixed with a eutectic reducing element (A) and bind the particles into a green form part with a specified shape, said particles each having a plurality of grains that are bound together along grain boundaries;

    partially reducing the carbon precursor such that a thin carbon (C) film remains whose C═

    C bonds maintain the part'"'"'s specified shape and acts as a catalyst causing the eutectic reducing element to become diffusely mobile;

    diffusing the eutectic reducing element along the particles'"'"' grain boundaries such that the reducing element interacts with the carbon film at the interface between the particles to form organo-metallic bonds C═

    A that are much stronger than the film'"'"'s C═

    C bonds; and

    initiating supersolidus liquid phase sintering (SLPS) to form a liquid film along the particles'"'"' grain boundaries so that the grains slide relative to each other and densify in response to surface tension and capillary pressure to form a final part whose organo-metallic C═

    A bonds maintain the specified shape.

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