Fe-Ga alloy is an advanced magnetostrictive material for actuators and sensors in terms of combining excellent mechanical and magnetostrictive properties. It is desirable to produce η(<100>//RD) textured Fe-Ga sheets due to the magnetostriction anisotropy with the largest coefficient along <100> direction and the serious eddy current loss in high-frequency use1,2. Current methods of promoting η texture in Fe-Ga alloy mainly include: (I) Micron-sized NbC particles were added to inhibit the normal grain growth, while the abnormal grain growth (AGG) of Goss ({110}<001>) texture was induced by surface energy effect from H2S atmosphere3-5. (II) Micron-sized NbC particles were precipitated, and AGG of Goss texture was induced by the surface energy effect under sulfur atmosphere6,7. (III) Nanometer-sized sulfides were dispersedly precipitated during rolling, and AGG of Goss texture was produced by the degrading pinning effect of inhibitor8-10. However, two-stage cold rolling and intermediate annealing processes are indispensable to regulating microstructure and texture in Fe-Ga alloy sheets. Distinct from the current methods in Fe-Ga alloy, a primary cold rolling method with a large reduction ratio was used in the grain-oriented silicon steel to produce sharp Goss texture with a lower deviation angle11,12. The nanometer-sized inhibitors are precipitated at hot rolling and normalization to induce secondary recrystallization of Goss grains.
In this paper, sharp Goss texture is successfully produced in Fe-Ga alloy sheet by primary cold rolling with a reduction ratio of ~85%. The nanometer-sized composite inhibitor was precipitated during rolling and annealing to induce secondary recrystallization of Goss texture. Nanometer-sized sulfides and NbC are dispersedly precipitated during hot rolling and normalization as inhibitors for secondary recrystallization. Fine grains textured by strong {111}<112> distributed through sheet thickness in primarily annealed sheets, which can provide a favorable environment for secondary recrystallization. Centimeter-sized Goss grains and large magnetostriction coefficient are obtained in Fe-Ga alloy by conventional primary cold rolling and annealing methods without surface energy effect.
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