Correlation of Fine Scale Microstructure
and Mechanical Properties
of Copper-Alumina Nanocomposites
R. Goswami, S. B. Qadri, and H. Ryou
Abstract Considerable efforts have been made to manufacture metal matrix
composites (MMCs) in the solid state to enhance the mechanical properties by
adding various volume fractions of alumina powder to achieve higher homogeneity of
ceramic particles in the matrix. Here, we present the fine scale microstructure, interfacial characteristics and mechanical properties of the copper-alumina composite. The
fine scale microstructure was characterized by transmission electron microscopy
(TEM) to study the nature of oxide precipitates formed during internal oxidation
of copper–aluminum alloy. We used nanoindentation to obtain the hardness and
modulus of the composite and demonstrated that the enhancement of strength mostly
stems from the nanocrystalline oxide particles. Furthermore, we observed that the
elastic modulus of the composite is 15% greater that of the commercially pure
copper. The improvement in modulus is shown to be associated with the formation of nanocrystalline coper oxide (Cu 2 O) or copper–oxygen (Cu–O) clusters in
copper matrix.
Keywords Microstructure · Interfaces · Metal matrix composite · Transmission
electron microscopy · Copper base alloys · Ceramic particulates
Introduction
Ceramic materials, such as silicon carbide, aluminum oxide and boron carbide, are
lightweight materials with considerably high compressive strength. As the weight
reduction is critical, considerable efforts have been made to manufacture metal matrix
composites (MMCs) with higher volume fractions of ceramic particulates [1, 2]. In
particular, various volume fractions of boron carbide (B 4 C) or silicon carbide (SiC)
powder have been added in the solid state to enhance the mechanical properties and to
achieve higher homogeneity of the composites. Considerable work has been carried
out on Al-based MMCs reinforced with B 4 C and SiC particles [2–4], and in all cases,
R. Goswami (B) · S. B. Qadri · H. Ryou
Materials Science and Technology Division, Naval Research Laboratory [NRL], Washington, DC
20375, USA
e-mail: Ramasis.Goswami@nrl.navy.mil
© The Minerals, Metals & Materials Society 2021
T. S. Srivatsan et al. (eds.), Metal-Matrix Composites, The Minerals, Metals
& Materials Series, https://doi.org/10.1007/978-3-030-65249-4_9
133
and Mechanical Properties
of Copper-Alumina Nanocomposites
R. Goswami, S. B. Qadri, and H. Ryou
Abstract Considerable efforts have been made to manufacture metal matrix
composites (MMCs) in the solid state to enhance the mechanical properties by
adding various volume fractions of alumina powder to achieve higher homogeneity of
ceramic particles in the matrix. Here, we present the fine scale microstructure, interfacial characteristics and mechanical properties of the copper-alumina composite. The
fine scale microstructure was characterized by transmission electron microscopy
(TEM) to study the nature of oxide precipitates formed during internal oxidation
of copper–aluminum alloy. We used nanoindentation to obtain the hardness and
modulus of the composite and demonstrated that the enhancement of strength mostly
stems from the nanocrystalline oxide particles. Furthermore, we observed that the
elastic modulus of the composite is 15% greater that of the commercially pure
copper. The improvement in modulus is shown to be associated with the formation of nanocrystalline coper oxide (Cu 2 O) or copper–oxygen (Cu–O) clusters in
copper matrix.
Keywords Microstructure · Interfaces · Metal matrix composite · Transmission
electron microscopy · Copper base alloys · Ceramic particulates
Introduction
Ceramic materials, such as silicon carbide, aluminum oxide and boron carbide, are
lightweight materials with considerably high compressive strength. As the weight
reduction is critical, considerable efforts have been made to manufacture metal matrix
composites (MMCs) with higher volume fractions of ceramic particulates [1, 2]. In
particular, various volume fractions of boron carbide (B 4 C) or silicon carbide (SiC)
powder have been added in the solid state to enhance the mechanical properties and to
achieve higher homogeneity of the composites. Considerable work has been carried
out on Al-based MMCs reinforced with B 4 C and SiC particles [2–4], and in all cases,
R. Goswami (B) · S. B. Qadri · H. Ryou
Materials Science and Technology Division, Naval Research Laboratory [NRL], Washington, DC
20375, USA
e-mail: Ramasis.Goswami@nrl.navy.mil
© The Minerals, Metals & Materials Society 2021
T. S. Srivatsan et al. (eds.), Metal-Matrix Composites, The Minerals, Metals
& Materials Series, https://doi.org/10.1007/978-3-030-65249-4_9
133