Improvement of the Operational Properties of Sintered Copper Steel Through the Use of an Efficient Alloying Method

Introduction. The alloying of powder steels, unlike cast steels, has a number of characteristic features due to the specifics of their preparation. The method of introducing the alloying component into the charge has a significant effect on the compactability, compressibility, structure and properties of sintered alloy steels.
Problem Statement. Existing alloying methods often do not provide a uniform distribution of alloying elements over the volume of the powder mixture, which leads to uneven density and a decrease in the strength properties of sintered steel.
Purpose. The purpose of research is to improve the technological properties of powder mixtures by using the most effective method for alloying sintered steels with copper 
Materials and Methods. As initial materials, we used sprayed iron powders of the ПЖР 3.200.28 grade (GOST-9849-86) and steel powder 70, which have low formability and green strength. A copper coating on iron powder particles was obtained by internal electrolysis (chemical cementation) in an acidic aqueous solution of copper sulfate with the addition of ferrous sulfate (II). Mechanosynthesis was carried out in a planetary ball mill. The technological properties of the powders were determined by standard methods: flowability ISO 4490, bulk density ISO 3923, compressibility ISO 3927, green strength ISO3995.
Results. The research has been done in regard to the set of technological and physical properties of powder materials, as well as the mechanical characteristics and the structure of sintered construction materials obtained through the use of various technological methods of alloying with copper and carbon: mechanical mixing, mechanosynthesis and copperizing (chemical cementation). A comparative analysis the properties of the materials obtained has been carried out and the optimal alloying method has been determined. It has been established that powder materials alloyed using the chemical cementation method have the highest level of technological and mechanical characteristics.
Conclusion. Chemical cementation alloying method can be recommended for the industrial production of sintered construction copper steels, since the use of it provides a high level of mechanical properties of the material and makes economic sense.

1. Yermakov, S. S., Vyaznikov, N. F. (1990). Powder steel and parts. Leningrad: Mashynostroenie [in Russian].
2. Radomyselskiy, I. D., Serdyuk, G. G., Shcherban, N. I. (1985). Constructive Powder Materials. Kyiv: Tekhnika [in Russian].
3. Stepanchuk, A. N., Bilyk, I. I., Boyko, P. A. (1989). Powder Metallurgy Technology. Kyiv: Vyshcha Shkola, 1989 [in Russian].
4. Antsiferov, V. N., Akimenko, V. B., Grevnov, L. M. (1991). Alloy Powder Steel. Moscow: Metallurgy [in Russian].
5. Antsiferov, V. N., Cherepanova, T. G. (1981). Sintered steel structure. Moscow: Metallurgy [in Russian].
6. Kreshchik, V. S., Klimenko, O. T. (1972). Ceramic-metal construction materials Kyiv: Naukova dumka [in Russian].
7. Trudel, Y., Angers, R. (1975). Comparitive Study of Fe-Cu-C Alloys Made from Mixed Prealloyed Powders. Intern. J. Powder Met., 2, 315.
8. Berner, D., Exner, H. E., Petzow, G. (1974). Modern Development in Powder Metallurgy. Swelling of Iron-Copper Mixtures During Sintering and Infiltration. Metal Powder Industries Federation, 6, 237.
9. Phadke, V. B., Davies, B. L. (1977). Comparing Diffusion and Penetration Theories of Growth in P/M Iron-Copper Alloys. Int. J. Powder Met. and Powder Technol., 4(13), 21–26.
10. Vnukov, A. A. (2015). Features of the mechanical alloying process application to obtain powder charge materials based on the Fe-Cu-C system. News of the National Technical University “KhPI”, 49, 3–6 [in Russian].
https://doi.org/10.15587/2312-8372.2015.53960
11. Kuzmich, Yu. V., Kolesnikova, I. G., Serba, V. I., Freydin, B. M. (2005). Mechanical alloying. Moscow: Nauka [in Russian].
12. Benjamin, J., Mercer, P. (1970). Dispersion strengthened superalloys mechanical alloying. Metall. Trans. A., 10(1), 2943-2951.
13. Shingu, Р. (1991). Mechanical alloying. Solid State Phys., 4(26), 55–59.
14. Shingu, H. (1991). Mechanical alloying. Jap. Soc. Technol. Plast., 368(32), 1116–1120.
15. Gaffet, E., Malhouroux-Gaffet, N., Abdellaoui, M., Malchere, A. (1994). Transitions de phases sous solicitations mecaniques: elaboration par mecanosynthese de materiaux a nanostructures (alliages metalliques, semiconducteurs, ceramiques). Rev. met., 5(91), 757-769.
https://doi.org/10.1051/metal/199491050757
16. Sundaresan, R., Froes, F. (1987). Mechanical alloying. J. Metals., 8, 22-27.
https://doi.org/10.1007/BF03258604
17. Murty, B. (1993). Mechanical alloying - a novel synthesis route for amorphous phases. Bull. Mater. Sci., 1(16), 1-17.
https://doi.org/10.1007/BF02745302
18. Ketov, V. M., Vnukov, A. A., Demchenko, E. I., Roslik, I. G. (March, 2011). Investigation of the influence of the copper alloying method on the powder blends properties and the characteristics of sintered materials based on iron. International Symposium "Surface Engineering. New powder composite materials. Welding". March, 23-25, Minsk, Belorussia. 153-157 [in Russian].
19. Vnukov, A. A. (2015). The structure and properties of sintered materials based on the Fe-Cu-C system obtained using various alloying methods. International scientometric journal "Technology audit and production reserves", 6, 85-89 [in Russian].
https://doi.org/10.15587/2312-8372.2015.53960
20. Svenssan, L. E. (1974). The Effect of Copper and Nickel Additions to High-Compressibility Sponge Iron Powder on the Sintered Properties of Materials with 0.3 and 0.6% Carbon. Powder Met., 17, 271.
https://doi.org/10.1179/pom.17.34.1974.002
21. Phadke, V. B., Davies, B. L. (1977). Precipitation Hardening in Sintered Iron-Copper Alloys. Powder Metallurgy International, 2(9), 38.
22. Colterell, В., Chotchov, Y., Mai, Y. W. (1985). Creep properties of Sintered Copper Steel. Journal of Materials Science, 9(20), 3409-3417.
https://doi.org/10.1007/BF00545210
23. Akimenko, V. B., Bulanov, V. Ya., Rukin, V. V. (1982). Iron powders. Technology, structure, properties, economics. Moscow: Nauka [in Russian].
24. Naboychenko, S. S. (1997). Non-ferrous metal powders. Moscow: Metallurgy [in Russian].