Microstructures and magnetostriction of two-phase Fe66-Pd 30-Ni4 high-temperature ferromagnetic shape memory alloys

Yin Chih Lin, Chien Feng Lin, Jin Bin Yang, Hwa Teng Lee

研究成果: Article同行評審

5 引文 斯高帕斯(Scopus)

摘要

The microstructures and magnetostrictive strains of ferromagnetic shape memory Fe-Pd30 alloy systems with additions of Ni elements (4 at.) have been investigated by a magnetostriction meter, scanning electron microscopy (SEM), x-ray diffraction (XRD), and transmission electron microscopy (TEM). The research results show that the magnetostrictive strains of the Fe 66-Pd30-Ni4 alloys after homogenization treatment (λ s = 79 10 - 6) are higher than those of the as received materials (λ s = 55 10 - 6). The lower magnetostriction of the as received metal is due to segregation-impeded parts of the L10 twin boundary motion in realistic magnetic fields. In addition, an important discovery in this study is that doping the Fe-Pd30 alloy system with Ni substitution for Fe seems to prevent the decomposition of L10 L1m twin phase into stoichiometric L10 L1m bct structures when the strain-forged alloys are solution treated and recrystallization annealed, and then aged at 400 C for 100 hours. The magnetostrictive strains of the 400 °C/100 h aged sample are maintained with λ s = 62 10 - 6; s = - 11 10 - 6, and the XRD analysis revealed a complete absence of bct phasein the aged sample. This magnetic property of the alloys is suitable for application in a high temperature and high frequency (T400 C) environment. The strain-forged samples were solution treated (ST) and recrystallization annealed, and then aged at 500∼700 °C for 100 hours. XRD analysis revealed the formation of an bct phase when the specimen was aged at 500 C for 100 hours. This αbct phase occurrence causes large reductions in the magnetostrictive strains. When the samples were aged at 600∼700 C for 100 hours, overaging occurred, the martensitic stoichiometric L10 L1m αbct lamellar structures dissolved into the matrix simultaneously, and the magnetostrictive strains gradually recovered.

原文English
文章編號07A912
期刊Journal of Applied Physics
109
發行號7
DOIs
出版狀態Published - 2011 4月 1

All Science Journal Classification (ASJC) codes

  • 一般物理與天文學

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