Thermal Stability of the Structure and Microhardness of the Al–0.05 vol % Al2O3 Nanocomposite Fabricated by Accumulative Roll Bonding
| Autor: | T. A. Kalashnikova, E. A. Glazkova, S. V. Fortuna, K. V. Ivanov |
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| Rok vydání: | 2019 |
| Předmět: |
010302 applied physics
Materials science Nanocomposite Annealing (metallurgy) Metals and Alloys 02 engineering and technology Microstructure 01 natural sciences 020501 mining & metallurgy Surfaces Coatings and Films Accumulative roll bonding Precipitation hardening 0205 materials engineering Mechanics of Materials 0103 physical sciences Hardening (metallurgy) Grain boundary Thermal stability Composite material |
| Zdroj: | Russian Journal of Non-Ferrous Metals. 60:524-530 |
| ISSN: | 1934-970X 1067-8212 |
| DOI: | 10.3103/s1067821219050110 |
| Popis: | The evolution of the microstructure and microhardness of the Al–0.05 vol % nAl2O3 nanocomposite (where nAl2O3 are aluminum nanoparticles) and aluminum without nanoparticles fabricated by accumulative roll bonding with annealing in a temperature range of 373–573 K is investigated. Ball-shaped Al2O3 nanoparticles with an average diameter of 50 nm are introduced between rolled plates of technically pure aluminum from the first to fourth rolling cycles, while the fifth to the tenth rolling cycles are performed without nanoparticles. The average grain size and aspect ratio of elements of the material grain–subgrain structure in the initial state and after annealing at 473 K are measured using transmission electron microscopy. It is shown that the nanocomposite microhardness is 5–13% higher than the corresponding value of HV for aluminum over the entire studied annealing temperature range. The main factor of the higher nanocomposite microhardness is precipitation hardening due to Al2O3 nanoparticles. The contribution of the substructural and grain-boundary hardening is identical in both materials. The thermal stability of the nanocomposite microhardness is only ~25 K higher than that of aluminum, which is caused by the nonuniform distribution of nanoparticles in the matrix and their low volume fraction. The high thermal stability of the fine-grain structure itself, formed by accumulative roll bonding, when compared with other methods of intense plastic deformation, also plays a role. It is established that most Al2O3 nanoparticles remain at the grain boundaries of nanocomposite after annealing at 473 K; therefore, the ability to fasten the boundary by Al2O3 nanoparticles under the conditions under study is retained at least to 473 K. |
| Databáze: | OpenAIRE |
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