TY - JOUR
T1 - Microstructures and magnetostriction of two-phase Fe66-Pd 30-Ni4 high-temperature ferromagnetic shape memory alloys
AU - Lin, Yin Chih
AU - Lin, Chien Feng
AU - Yang, Jin Bin
AU - Lee, Hwa Teng
N1 - Funding Information:
The authors would like to express their sincere appreciation to the National Science Council of the Republic of China for supporting this study (NSC-99-2221-E-151-017).
PY - 2011/4/1
Y1 - 2011/4/1
N2 - 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.
AB - 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.
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U2 - 10.1063/1.3540690
DO - 10.1063/1.3540690
M3 - Article
AN - SCOPUS:79955412906
SN - 0021-8979
VL - 109
JO - Journal of Applied Physics
JF - Journal of Applied Physics
IS - 7
M1 - 07A912
ER -