Metal matrix composite materials (MMC) are a promising class of materials that combine high strength, rigidity, and heat resistance of metal with improved characteristics provided by reinforcing components. This paper explores the possibility of creating and studying the properties of MMC based on an aluminum matrix reinforced with gas-atomized powders of Al-Cu-Fe alloy.
The choice of Al-Cu-Fe alloy as a reinforcing component is due to its unique properties, such as high hardness, wear resistance and thermal stability. Gas-atomized powders ensure uniform distribution of the reinforcing phase in the matrix, which helps to improve the mechanical characteristics of the composite.
The powder metallurgy method was used to obtain the CMM, which includes mixing aluminum matrix and Al-Cu-Fe alloy powders, pressing the resulting mixture, and subsequent sintering in a protective atmosphere. Varying the content of the reinforcing phase allows optimizing the properties of the composite depending on specific application requirements.
To create powders with an icosahedral quasicrystalline structure, the Al62Cu26Fe12 alloy was sprayed in a gas environment. The resulting Al62Cu26Fe12 powders were used as a reinforcing phase in the creation of composite materials, where the matrix was pure aluminum. During casting, the powders were added to molten aluminum. The application of a nickel coating with a thickness of about 5 micrometers on the Al62Cu26Fe12 particles played a key role in preserving their original structure during casting. The resulting composites demonstrated a sufficiently strong bond between the Al62Cu26Fe12 particles and the aluminum matrix, even with partial dissolution of small secondary particles. Compression and indentation tests revealed a significant increase in the yield strength of the composites, especially at a concentration of reinforcing particles of up to 10% by volume. The strengthening mechanisms are analyzed to determine the contribution of icosahedral and associated crystalline phases to the increase in the yield strength of the material.
As a result of the conducted studies, CMMs with different contents of the reinforcing phase were obtained. Microstructure analysis showed uniform distribution of Al-Cu-Fe powders in the aluminum matrix. Measurement of mechanical properties revealed an increase in hardness and tensile strength with an increase in the content of the reinforcing phase.
The obtained CMMs can be used in various fields of technology where a combination of high strength, wear resistance and thermal stability is required, for example, in the aviation and automotive industries.
Author: SM Lee, JH Jung, E Fleury, WT Kim, DH Kim
Institute: Department of Metallurgical Engineering, Center for Non-Crystalline Materials, Yonsei University, 134 Shincheon-dong, Seodamun-gu, Seoul 120-749, South Korea