Effect of Initial Oriented Columnar Grains on the Texture Evolution and Magnetostriction in Fe–Ga Rolled Sheets

Jiheng Li,Xiaoqian Bao,Chao Yuan,Qingli Qi,Xuexu Gao

doi:10.3390/met7020036

Abstract

The effects of initial oriented columnar grains on the texture evolution and magnetostriction in (Fe83Ga17)99.9(NbC)0.1 rolled sheets were investigated. The recrystallization texture evolution exhibited the heredity of initial orientations, concerning the formation of cube and Goss textures in the primary recrystallized sheet for the columnar-grained sample. Moreover, the growth advantage of Goss grains was more obvious than that of cube grains during the secondary recrystallization process. Because of the combined effect of this and Nb-rich precipitates as inhibitors, a sharp Goss texture and very large Goss grains were achieved in the secondary recrystallized sheet for the columnar-grained sample. For comparison, the secondary recrystallization in the equiaxed-grained sample was not fully developed although there were Nb-rich precipitates as inhibitors. We think this could be ascribed to the large particle size and premature coarsening of precipitates. Magnetostriction of the secondary recrystallized columnar-grained sheet was up to 232 ppm owing to the ideal Goss texture and quite large grain size. As for the equiaxed-grained sample, the magnetostriction was only 163 ppm in the secondary recrystallized sheet.

Highlights

Magnetostrictive Fe–Ga alloys (Galfenol) have received increasing attention—a new kind of magnetostrictive smart material for actuator, sensor, and energy harvesting applications [1,2].These interests stem from the fact that, unlike existing smart material systems, Galfenol is the first kind of material that shows a good combination of magnetostrictive properties and mechanical properties.The addition of Ga increases the magnetostrictive capability of Fe over tenfold up to 400 ppm (×10−6 )along the direction in single crystal material [3]
In the specimen fabricated by directional solidification, some columnar grains with a width above 1000 μm are distributed homogeneously, as shown in the longitudinal optical photograph (Figure 2a)
The grain boundary is parallel to the drawing direction, because the grain morphology of the directionally solidified specimen is related to the direction of heat dissipation

Summary

Introduction

Magnetostrictive Fe–Ga alloys (Galfenol) have received increasing attention—a new kind of magnetostrictive smart material for actuator, sensor, and energy harvesting applications [1,2].These interests stem from the fact that, unlike existing smart material systems, Galfenol is the first kind of material that shows a good combination of magnetostrictive properties and mechanical properties.The addition of Ga increases the magnetostrictive capability of Fe over tenfold up to 400 ppm (×10−6 )along the direction in single crystal material [3]. Goss texture and quite work, effects of the initial oriented columnar grains on texture evolution and magnetostriction in large the Goss grains are achieved the secondary recrystallized alloy sheets, resulting in a high magnetostriction.

Results

Conclusion