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Fabrication of Graded Nickel–Alumina Composites with a Thermal‐Behavior‐Matching Process
Author(s) -
Winter Andrew N.,
Corff Brian A.,
Reimanis Ivar E.,
Rabin Barry H.
Publication year - 2000
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.2000.tb01528.x
Subject(s) - materials science , sintering , composite material , fabrication , compaction , composite number , consolidation (business) , microstructure , shrinkage , nickel , mold , pressing , hot isostatic pressing , hot pressing , thermal , metallurgy , medicine , alternative medicine , physics , accounting , pathology , meteorology , business
Composites of nickel and Al 2 O 3 with compositionally graded microstructures were fabricated from powders through an empirically determined thermal‐behavior‐matching process that was designed to minimize processing‐induced stresses. Compositions ranged from pure Al 2 O 3 to pure nickel. Specimen geometries included round disks 25 mm in diameter and 5–25 mm thick, as well as rectangular bars 25 mm × 25 mm in cross section and 75 mm long. Several different gradients were produced, including samples with single interlayers. Compacts were formed by cold uniaxial pressing in a die, followed by consolidation through sintering at 1 atm or hot isostatic pressing. Several different particle sizes of nickel and Al 2 O 3 comprised the composite interlayers. The compaction behavior, sintering start temperature, sintering rate, and total linear shrinkage of each composition were evaluated. Careful data analysis, coupled with sintering theory, led to a layer configuration with matched green density and sintering behavior. Thermomechanically matched layers allowed large, crack‐free, graded composites to be produced.