Nickel-Alumina Composites: In Situ Synthesis by a Displacement Reaction, and Mechanical Properties

Abstract

Nickel-alumina composites have the potential to be high performance materials. Alumina, with its excellent oxidation resistance, combined with a ductile phase such as nickel may provide a tough material with a lower density and higher Young's modulus, overall, a higher specific modulus than typical Superalloys. Dense, interpenetrating Ni-Al2O3 composites were synthesized using a displacement reaction between NiO and aluminum. The resulting composites were characterized in terms of their mechanical properties such as hardness, flexure strength, fracture toughness and elastic constants. The synthesis, characterization, and mechanical properties, as well as the effect of the interpenetrating microstructure on the toughening mechanisms and other properties will be discussed.

Reactive Processing in Ceramic‐Based Systems

“…Compared with the methods summarized in Table I, RHP has the advantage of increased compositional flexibility. [44][45][46][47][48][49][50][51][52][53] Single-or multiphase materials containing oxide ceramics, nonoxide ceramics, intermetallics, and/or metals can be formed by RHP. 44,50,54,55 Often, RHP results in the formation of favorable two-phase, interpenetrating microstructures.…”

“…Several research groups have produced a variety of composites by RHP including Al 2 O 3 -Ni, Al 2 O 3 -Nb, Al 2 O 3 -MoSi 2 , ZrB 2 -SiC, and SiC-Nb 2 Si. [44][45][46][47][48][49][50][51][52][53] Often, the temperature required to produce a composite reactively is much lower than for non-RHP of the same composition. For example, dense Al 2 O 3 -MoSi 2 composites can be produced by RHP at 14501C, 51 compared with 17001C for non-RHP.…”

Particle-Reinforced Ceramic Matrix Composites—Selected Examples

“…In particular, the ceramic-metal system links materials of different chemical and physical properties, including chemical bonds. Despite these differences between ceramics and metals, which are not favorable in the fabrication process of ceramic-metal composites, they have been investigated for many years, and the basic knowledge about their structure, properties, and directions of development has been well documented [1][2][3][4]. The most important reason for these studies is to elaborate ceramic-metal composites with the desired properties, such as improved fracture toughness, high hardness, and good mechanical (bending strength) and tribological properties [5][6][7][8][9].…”

Análisis de la fragmentación de cermets de alúmina–níquel ensayados en Barra Hopkinson a altas velocidades de deformación

“…Para lograr un refuerzo eficiente, se requiere sin embargo un alto nivel de dispersión de la fase dúctil en la matriz para lograr una alta densidad relativa. Los materiales compuestos de alúmina-níquel se han preparado por varios métodos, incluyendo el procesamiento por sol-gel [4][5], sinterización sin presión, [6][7], la reducción de NiAl 2 O 4 [8], el prensado en caliente reactivo [9][10] o la reacción de En este trabajo, se presenta un estudio comparativo de la influencia de la velocidad de deformación sobre el comportamiento mecánico a la fragmentación de materiales compuestos de una matriz de alúmina con níquel metálico disperso cuando son sometidos a elevadas velocidades de deformación. La fragmentación bajo cargas dinámicas de compresión a alta velocidad se ha realizado mediante una Barra Hopkinson (SHPB).…”