Study of vacancies in Fe-x(CoCrMnNi)(100-x) medium- and high-entropy alloys by positron annihilation spectroscopy
Abstrakt
A study of vacancies in Fe-x(CoCrMnNi)(100-x) medium- and high-entropy alloys by positron annihilation spectroscopy (PAS) was carried out. Positron lifetime studies showed that specimens of Fe-x(CoCrMnNi)(100-x) alloys (x = 20, 40, 50, 60) contain monovacancies characterized by positron lifetime of approximate to 170 ps.
The alloys with a composition closer to equimolar, i.e. with lower Fe content, exhibited higher configurational entropy and a lower concentration of monovacancies. This was related to the dependence of the vacancy formation enthalpy on Fe content in the Fe-x(CoCrMnNi)(100-x) system.
Coincidence Doppler broadening revealed that Mn content is enhanced in the vicinity of vacancies. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd.
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