Texture Control Of Secondary Recrystallization And Performance Optimization In Fe₈₁Ga₁₉ Alloy Warm Rolling Sheet

Magnetostrictive materials are closely related to national economy and security.Fe-Ga alloy(Galfenol)is the only new magnetostrictive material known to have both giant magnetostriction coefficient and excellent mechanical properties,it has been widely concerned in recent years.The magnetostrictive property of Fe-Ga alloy has significant anisotropy,and the magnetostriction coefficient is the largest in<100>direction.The Fe81Ga19 alloy sheet prepared by rolling has the characteristics of high efficiency and low cost.The Fe81Ga19 alloy is brittle and difficult to roll.The magnetostrictive property is closely related to the area fraction and orientation of the secondary recrystallized Goss({110}<100>)texture.Therefore,the core technology for preparing Fe81Ga19 polycrystal sheet with excellent magnetostrictive property by rolling is stable forming and texture control.The current research on the secondary recrystallization of Fe-Ga alloy includes two aspects.On the one hand,use the rolling technology of warm rolling and cold rolling.On the other hand,design the inhibitor system of NbC and surface energy induction.However,on later stage of rolling,formability is bad when rolling at room temperature.Using surface segregation for surface energy induction and supplementary inhibitionurface,the high temperature annealing at 1200? is required to eliminate residual crystal grains,but the serious evaporation of Ga is not conducive to magnetostrictive property.Therefore,there is an urgent need to develop a stable and efficient method for preparing Fe-Ga alloy sheet with strong Goss texture.In this study,NbC and Cu2S composite inhibitor system and secondary warm rolling method was adopted,and successfully prepared Fe81Ga19 alloy sheet with strong Goss({110}<001>)secondary recrystallization texture by traditional hot rolling,cold rolling and annealing processes.X-ray diffraction and EBSD was used to study two important problems of secondary recrystallization texture control and stable forming of Fe81Ga19 alloy prepared by rolling method.The main conclusions are as follows:(1)Based on the intrinsic composite inhibitor system(NbC+Cu2S),the nano-sized second phase was precipitated in the primary recrystallized Fe81Ga19 alloy sheet by composition design,rolling and annealing atmosphere.By adjusting the matching of secondary recrystallization driving force and inhibition force,Fe81Ga19 alloy sheet with strong Goss texture and excellent magnetostrictive property was successfully prepared at low temperature.(2)With the increase of H2 content in the high temperature annealing atmosphere,the secondary recrystallization starting temperature decreased,and the secondary recrystallization completion temperature was the lowest in the 50%H2 annealing atmosphere.It was difficult to obtained completed secondary recrystallization in the 100%H2 annealing atmosphere.It was mainly attributed that as the H2 content increased,the inhibition loss rate and the matrix grain size increased,resulting in decreasing the driving force of secondary recrystallization,and finally it was difficult to engulf the oversized residual grains.(3)As the rolling temperature increased,the number of shear bands increased first and then decreased,and primary recrystallization grain size increased,and the secondary recrystallization driving force decreased,and the start temperature of secondary recrystallization increased,but the strength of the inhibitor system ensured that the secondary recrystallization could be completed with different rolling temperature.(4)In this study,the Fe81Ga19 alloy sheet with strong Goss texture was prepared at low temperature by the coordination of the inhibitor-microstructure-texture.At 600? warm rolling,rapid stable forming and secondary recrystallization texture control were realized,which indicated a feasible path for the industrial production of strong Goss textured Fe81Ga19 alloy sheet.