L. G. Korshunov, N. L. Chernenko, I. G. Brodova, I. G. Shirinkina

EFFECT OF SEVERE PLASTIC DEFORMATION AND OXIDATION ON THE STRUCTURE AND MICROHARDNESS OF THE SILUMIN SURFACE LAYER

Structural changes occurring in the surface layer, up to 10 μm thick, of silumin (Al–17 % Si alloy) in the case of deformation under sliding friction and subsequent oxidation at 100 and 200 °C for 1 hour are studied by metallographic analysis, X-ray diffraction analysis and electron microscopy. Frictional deformation was carried out in air at room temperature and in liquid nitrogen (at −196 °C). Deformation under these conditions is shown to form a nanocrystalline structure in the surface layer of the Al–17 % Si alloy and to increase its microhardness by a factor of 1.8. In the alloy surface under friction, severe plastic deformation, as well as the high affinity of oxygen to aluminum and silicon, initiates the appearance of anomalously supersaturated solid solutions of oxygen in aluminum and silicon. Oxidation of the deformed Al–17 % Si alloy at 100 °C for 1 hour increases its microhardness as a result of the decomposition of anomalously supersaturated solid solutions of oxygen in aluminum and silicon and the formation of their oxides.

References:

1. Korshunov L.G., Makarov A.V., Chernenko N.L. Nanocrystalline friction structures in steels and alloys, their mechanical and tribological properties. In: Razvitie idey akademika V.D. Sadovskogo [Developing the Ideas of Academician V.D. Sadovsky]. Ekaterinburg, Institute of Metal Physics, UB RAS, Publ., 2008, 409 p. (In Russian).
2. Dong Y., Bell T. Enhanced wear resistance of titanium surfaces by a new thermal oxidation treatment. Wear, 2000, vol. 238, pp. 131–137.
3. Korshunov L.G., Chernenko N.L. Formation of a wear-resistant nanocrystalline layer strengthened by TiO2 (Rutile) particles on the surface of titanium. Physics of Metals and Metallography, 2013, vol. 114, no. 9, pp. 789–797. DOI: 10.1134/S0031918X13070065.
4. Metin Е., Inal O.T. Kinetics of layer growth and multiphase diffusion in ion nitrided titanium. Metal. Mater. Trans., 1989, vol. 20А, no. 9, pp. 1819–1832.
5. Korshunov L.G., Shabashov V.A., Chernenko N.L., Pilyugin V.P. Effect of contact stresses on the phase composition, strength, and tribological properties of nanocrystalline structures formed in steels and alloys under sliding friction. Metal Science and Heat Treatment, 2008, vol. 5, nos. 11–12, pp. 583–592. DOI: 10.1007/s11041-009-9103-2.
6. Vol A.E. Stroenie i svoistva dvoinykh metallicheskikh system [The Structure and Properties of Binary Metal Systems]. Moscow, Gosudarstvennoe Izdatelstvo Fiziko-Matematicheskoy Literatury Publ., 1959, 755 p. (In Russian).
7. Entsiklopediya neorganicheskikh materialov. Tom 1 [Encyclopedia of Inorganic Materials, vol. 1]. Kiev, Glavnaya Redaktsiya Ukrainskoy Sovetskoy Entsiklopedii Publ., 1977, 840 p. (In Russian).
8. Pugacheva N.B., Vichuzhanin D.I., Kalashnikov S.T., Ivanov A.V., Smirnov S.V., Frolova N.Yu. Studying recovery processes in a strain-hardened Al–Mg–Mn–Fe–Si alloy. Physics of Metals and Metallography, 2016, vol. 117, no. 9, pp. 920–926. DOI: 10.1134/S0031918X16090076.

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