Study of the effect of dispersion and homogeneity of the structure on the properties of powder metastable austenitic carbide steels and diamond tools

Diffusion and homogenization in powder systems of varying degrees of dispersion «iron (5 μm) – nickel (5 μm or 50 nm)» during sintering (900 and 1000 °C), as well as spark plasma sintering using the Matano-Boltzmann method were studied. In these systems, the calculated diffusion coefficients in pairs of micron powders, sintered without application of pressure (900 °C, 6 h) and the spark plasma method (900 °C, 5 min), were equal to 7·10–10 cm2/s. It is shown that in diffusion pairs based on microdispersed iron powder, the use of nanodispersed nickel powder instead of microdispersed one contributes to an increase in the diffusion coefficient at a temperature of 900 °C by a factor of 2. The constants in the sintering kinetics equation of V.A. Ivensen are calculated for iron–nickel powder systems. Through them the factors activating the sintering of these systems were established. The dependences of the structure-phase composition and physicomechanical properties of carbides of the Fe (base) system — 14 wt.% Ni – 8 wt.% TiC system on the sintering temperature in the interval t = 900÷1200 °C, dispersion and homogeneity of the structure were determined. The dependences of grain size, porosity, hardness, microhardness, toughness, bending strength on sintering temperature are shown. The established dependences of the tribotechnical properties on the degree of homogeneity of the solid solution and the volume of the phase transformation of the metastable austenite to deformation martensite during friction on the abrasive were similar for carbide steels and diamond tools based on carbide steels. The optimal values of the coefficient of variation of nickel concentration in austenite in carbidostils of the same chemical composition, but different dispersion, providing the maximum amount of austenite decomposition and high values of the diamond tool grinding coefficient were 5 in both systems, but the sintering parameters differed. It is shown that the physicomechanical properties of the studied systems depend on the porosity and dispersion of the structure, and the tribotechnical properties are subjected to the homogeneity of the structure of the steel.

powdered carbide steels, diamond tools, micro- and nano-dispersed powders, nickel, titanium carbide, diffusion coefficient, activation energy, concentration inhomogeneity, metastable austenite, deformation martensite, structure, properties, grinding ratio

1. Schwartz M. Encyсlopedia of smart materials. N.Y.: Wiley, 2002.

2. Ponge D., MiUán J., Raabe D. Design of lean maraging TRIP steels. In: Advanced Steels. Berlin, Heidelberg: Springer, 2011. P. 199—208. https://doi.org/10.1007/9783-642-17665-4_21.

3. Raabe D., Ponge D, Dmitrieva O., Sander B. Nanoprecipitate-hardened 1.5 GPa steels with unexpected high ductility. Scr. Mater. 2009. Vol. 60. Iss. 12. P. 1141—1144. https://doi.org/10.1016/j.scriptamat.2009.02.062.

4. Roebuck B., Almond E.A., Cottenden A.M. The influence of composition, phase transformation and varying the relative FCC and HCP phase contents on the properties of dilute Co—W—C alloys. Mater. Sci. Eng. A. 1984. Vol. 66. Iss. 2. P. 179—194.

5. Konyashin I., Lachmann F., Ries B., Mazilkin A.A., Straumal B.B., Kübel Chr., Llanes L., Baretzky B. Strengthening zones in the Co matrix of WC—Co cemented carbides. Scr. Mater. 2014. Vol. 83. P. 17—20.

6. Konyashin I., Ries B. Wear damage of cemented carbides with different combinations of WC mean grain size and Co content. Part I. ASTM wear tests. Int. J. Refract. Met. Hard Mater. 2014. Vol. 46. P. 12—19.

7. Konyashin I., Ries B. Wear damage of cemented carbides with different combinations of WC mean grain size and Co content. Part II. Laboratory performance tests on rock cutting and drilling. Int. J. Refract. Met. Hard Mater. 2014. Vol. 45. P. 230—237.

8. Raabe D., Ponge D., Dmitrieva O., Sander B. Designing ultrahigh strength steels with good ductility by combining transformation induced plasticity and martensite aging. Adv. Eng. Mater. 2009. Vol. 11. No. 7. P. 547—555. DOI: 10.1002/adem.200900061.

9. Nambu S., Michiuchi M., Ishimoto Y., Asakura K., Inoue J., Koseki T. Transition in deformation behavior of martensitic steel during large deformation under uniaxial tensile loading . Scr. Mater. 2009. Vol. 4. No. 60. P. 221—224.

10. Antsiferov V.N., Bobrova S.N., Oglezneva S.A., Peshcherenko S.N., Timokhova A.P., Shatsov A.A. Problems of powder materials science. Pt. 1. Ekaterinburg: UrO RAN, 2000 (In Russ.).

11. Kikoin I.K. Tables of physical quantities. Moscow: Atomizdat, 1976 (In Russ.).

12. Tunshoff H.K., Hillmann-Apmann H., Asche J. Diamond tools in stone and civil engineering industry: cutting principles, wear and applications. Diamond Relat. Mater. 2002. Vol. 11. No. 3—6. P. 736—741.

13. Konstanty J., Duk Yong Yoon, Suk-Joong L. Kang, Kwang Yong Eun, Yong-Seog Kim. Powder metallurgy diamond tools — A review of manufacturing routes. Mater. Sci. Forum. 2007. Vol. 534—536. P. 1121—1124. https://doi. org/10.4028/www.scientific.net/MSF.534-536.1121.

14. Arzamasov B.N., Sidorin I.I., Kosolapov G.F. Materials science. Moscow: Mashinostroenie, 1986 (In Russ.).

15. Spriano S., Chen Q., Settineri L., Bugliosi S. Low content and free cobalt matrixes for diamond tools. Wear. 2005. Vol. 259. No. 7—12. P. 1190—1196.

16. Zaitsev A.A., Kurbatkina V.V., Levashov E.A. Features of the effect of nanodispersed additives on the sintering progress and properties of powdered cobalt alloys. Russ. J. NonFerr. Met. 2008. Vol. 49. No. 2. P. 120—125.

17. Konyashin I., Ries B., Hlawatschek D., Zhuk Y., Mazilkin A., Straumal B., Dorn F., Park D. Wear-resistance and hardness: are they directly related for nanostructured hard materials. Int. J. Refract. Met. Hard Mater. 2015. Vol. 49. P. 203—211.

18. Konyashin I., Ries B., Lachmann F., Cooper R., Mazilkin A., Straumal B., Aretz A., Babaev V. Hardmetals with nano-grain reinforced binder: binder fine structure and hardness. Int. J. Refract. Met. Hard Mater. 2008. Vol. 26. P. 583—588.

19. Oglezneva S.A., Bulanov V.Ya., Kontsevoi Yu.V., Ignat’ev I.E. Production of nickel and iron nanopowders by hydrogen reduction from salts. Russ. Metall. (Metally). 2012. No. 7. P. 654—658.

20. Antsiferov V.N., Mazein S.A. Study of the influence of mechanochemical activation in the titanium-carbon system. Fizika i khimiya obrabotki materialov. 1994. No. 4—5. P. 195—199 (In Russ.).

21. Oglezneva S.A., Portalov M.N. Investigation into the kinetics of isothermal sintering of milled and mechanically alloyed iron powders. Russ. J. Non-Ferr. Met. 2015. Vol. 56. No. 3. P. 300—306. DOI: 10.3103/S1067821215030153.

22. Oglezneva S.A. Rapid method for the determination of the diamond specific consumption under laboratory conditions. Izvestiya vuzov. Tsvetnaya metallurgiya. 2000. No. 5. P. 65—67 (In Russ.).

23. Khansen M., Anderko K. Double alloy structures. Moscow: Metallurgizdat, 1962 (In Russ.).

24. Matrenin S.V., Il’in A.P., Slosman A.I., Tolobanova L.O. Sintering of nano-dispersed iron powder. Perspektivnye materialy. 2008. No. 4. P. 81—87 (In Russ.).

25. Ivensen V.A. Phenomenology of sintering and some theory questions. Moscow: Metallurgiya, 1985 (In Russ.).