Mössbauer study of martensitic transformation and collective magnetic excitations in Fe.9Ni.1 fine particles

Mössbauer study of martensitic transformation and collective magnetic excitations in Fe.₉Ni.₁ fine particles

H.M. Widatallah，

Huang Run-Sheng，

Hsia Yuan-Fu，

Li Shi-Min，

Wang Jin-Hui，

Lu Huai-Xian

Nuclear Science and Techniques

Vol.7, No.4

pp.215-219

Published in print 01 Nov 1996

24000

The austenite to martensite transformation in fine Fe.₉₀Ni.₁₀ particles prepared by evaporation is studied by Mössbauer technique. Unlike bulk Fe.₉Ni.₁ which is entirely transformed to martensite, these particles show a remarkable austenite stability upon cooling upto liquid nitrogen temperature. This stability is associated with the oxide surface layer formed on the particles and also with their small size. A hyperfine field approach is employed to analyze the martensitic transformation in the particles. It is also shown that, in contrast with large particles, the temperature variation of the Mössbauer average hyperfine field of the fine particles can be satisfactorily explained in terms of the collective magnetic excitations model.

Mössbauer effectMartensiteAusteniteFe.9Ni.1Collective magnetic excitation modelHyperfine field

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