One step HIP canning of powder metallurgy composites
AssigneeThe United States of America as represented by the Administrator of the National Aeronautics and Space Administration
InventorJohn J. Juhas
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Abstract
A single step is relied on in the canning process for hot isostatic pressing powder metallurgy composites. The binders are totally removed while the HIP can of compatible refractory metal is sealed at high vacuum and temperature. This eliminates out-gassing during hot isostatic pressing.
Claims14
A method of canning a powder metallurgy composite containing binders prior to hot isostatic pressing comprising the steps of
- enclosing said composite with a metal frame adjacent the outer peripheral surface thereof,
- interposing said composite and frame between spaced face sheets to form an assembly,
- positioning said assembly in a die,
- loading said die and assembly into a vacuum hot press,
- heating said composite in a vacuum to a first temperture that is high enough to remove said binders,
- maintaining said composite at said first temperature in said vacuum until substantially all of said binders are removed,
- heating said composite to a second temperature that is substantially higher than said first temperature subsequent to the removal of said binders,
- maintaining said composite at said second temperature while deforming said frame and producing a solid state diffusion weld between said frame and said face sheets, and
- partially densifying said composites thereby establishing the geometry of the same.
In a method of hot isostatic pressing a metallurgy composite comprising layers of fibers and powders held together with binders, an improved canning process including
- removing said binders by heating said composite between face plates separated by a frame that surrounds said fibers and powders, and
- heating said composite in a vacuum to a higher temperature at which the frame is deformed and a solid state diffusion weld is produced between said face plate and said frame thereby partially densifying said composite to lock the fibers and powders in place in a can.
In a method of hot isostatic pressing a powder metallurgy composite containing binders, an improved canning process comprising
- enclosing said composite in a can, and
- removing said binders in said composite while simultaneously sealing said can so that no out-gassing will occur during hot isostatic pressing.
Dependencies are inferred from the claim text.