Embrittlement mechanisms and magnetic properties optimization conditions in amorphous Co69Ge3.7Cr3.8Si12.5B11 alloy without ductile-brittle transition
The influence of annealing time on the ductile-brittle transition temperature (embrittlement temperature) Т f in amorphous Co-based alloy Со69Fe3.7Cr3.8Si12.5B11 with extremely low saturation magnetostriction λ s (λ s < 10–7) is investigated. It is revealed that the embrittlement temperature Т f dependence on annealing time t a can be described by the Arrhenius equation. Embrittlement at annealing temperatures higher and lower than 300°С can be described by different kinetic parameters owing to the different states of the amorphous phase. It is shown that, in the studied alloy, the embrittlement proceeds in a very narrow annealing temperature range, not exceeding 5°С. On the basis of experimental data on the evolution of hysteresis magnetic properties during isochronous annealing and isothermal exposure, the thermal treatment mode is investigated, providing rather high values of permeability μ5 (Н = 5 mOe, f = 1 kHz) of about 50000, without transforming studied alloy into the brittle state.
Keywordsembrittlement of amorphous alloys kinetic parameters of embrittlement structural states of amorphous phase at different annealing temperatures evolution of hysteresis magnetic properties during thermal treatment
Unable to display preview. Download preview PDF.
- 1.Glezer, A.M. and Molotilov, B.V., Struktura i mekhanicheskie svoistva amorfnykh splavov (Structure and Mechanical Properties of Amorphous Alloys), Moscow: Metallurgiya, 1992.Google Scholar
- 2.Kekalo, I.B., Protsessy strukturnoi relaksatsii i fizicheskie svoistva amorfnykh splavov (Structural Relaxation and Physical Properties of Amorphous Alloys), Moscow: Mosk. Inst. Stali Splavov, 2014, vol. 1.Google Scholar
- 3.Small-Angle X-ray Scattering, Glatter, O. and Kratky, O., Eds., London: Academic, 1983.Google Scholar
- 4.Kekalo, I.B., Shuvaeva, E.A., and Egorova, E.A., Structural relaxation and embrittlement development in Co based soft-magnetic amorphous alloys, Mater. XXII mezhd. konf. “Relaksatsionnye yavleniya v tverdykh telakh,” Tezisy dokladov (Proc. 23rd Int. Conf. “Relaxation Effects in Solid Bodies,” Abstracts of Papers), Voronezh: Voronezh. Gos. Univ., 1999, pp. 109–110.Google Scholar
- 5.Kekalo, I.B., Basargin, O.V., and Tsvetkov, V.Yu., Dilatometric analysis of structure relaxation in amorphous alloys, Fiz. Met. Metalloved., 1984, vol. 57, no. 5, pp. 967–974.Google Scholar
- 6.Bokshtein, B.S., Kaputkina, L.M., Kovachev, G., et al., Kinetics of extra volume release in amorphous cobalt-based alloys, Fiz. Met. Metalloved., 1991, no. 12, pp. 75–79.Google Scholar
- 7.Kekalo, I.B., Mogil’nikov, P.S., Lubyanyi, D.Z., and Chichibaba, I.A., Processes of structural relaxation in the amorphous alloy Co9Fe3.7Cr3.8Si12.5B11 with a nearzero magnetostriction and their effect on the magnetic properties and the characteristics of magnetic noise caused by Barkhausen jumps, Phys. Met. Metallogr., 2015, vol. 116, no. 7, pp. 645–655.CrossRefGoogle Scholar
- 8.Guinen, A. and Fournet, G., Small-Angle Scattering X-rays, New York: Wiley, 1955.Google Scholar
- 10.Kimura, H. and Matsumoto, T., Strength, ductility, and toughness—a model study in mechanics, in Amorphous Metallic Alloys, Luborsky, F.E., Ed., London: Butterworth, 1983, p. 187.Google Scholar