Design of high ductility FeGa magnetostrictive alloys: Tb doping and directional solidification

Publication date: 15 September 2017
Source:Materials & Design, Volume 130
Author(s): Chongzheng Meng, Yuye Wu, Chengbao Jiang
Decent magnetostriction of ~255ppm and giant tensile strain of ~6.6% is obtained through trace Tb addition and directional solidification method in (Fe0.83Ga0.17)100−xTbx (x=0–0.5) alloys. The particle-shaped Tb-rich precipitates are formed and dispersively distributed in the matrix along the (sub-) grain boundaries; preferred 〈100〉 orientation is achieved in the alloys by appropriate directional solidification process, which makes contribution to improve the magnetostriction. The formation of Tb-rich precipitates induces the transition of the fracture mechanism from brittleness to ductility. The maximal room-temperature tensile strain is obtained in x=0.05 specimen, which is superior to existing literatures about the mechanical properties of Fe-Ga based alloys. The regular columnar grain morphologies and certain distribution pattern of granular precipitates are considered to be responsible for the excellent ductility in Fe-Ga-Tb alloys. This work may provide a new thinking to design high ductility Fe-Ga magnetostrictive alloys and significantly broaden the application of these materials in industry field.

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