| Fe-Ga alloy(Galfenol)has the advantages of low saturation magnetic field,high tensile strength,high magnetic permeability and good temperature characteristics,make Fe-Ga alloy become a better candidate in actuation,sensing,and energy harvesting applications in last decade.The magnetostrictive property shows significant anisotropy,magnetostriction coefficient along<001>direction reaches 400 ppm.It is expected that thin sheet featured of strong ? texture,obtained by rolling and secondary recrystallization,could reduce the serious eddy current loss led by high electrical conductivity.The micrometer-sized NbC particles are mainly precipitated or added as a main inhibitor,which is used to induce secondary recrystallization of Goss grains with help of the surface energy effect under the atmosphere of H2S or S element,thereby improving the magnetostrictive properties of the sheet.However,there is still a gap between the orientation of Goss grains in Fe-Ga and the of Goss grains in grain-orientated silicon steel in the current study,which is attributed to the match of inhibitor system and the grain boundary mobility of Fe-Ga alloy.In this paper,Fe-Ga alloy sheet with secondarily recrystallized Goss grain was prepared in first stage cold rolling method based on a composite inhibitor system and primary recrystallization texture.The composite inhibitor system is constructed by designing the content of micro-alloy element,rolling and annealing process.Combining macrostructure and micro structure,precipitated phase and texture characterization methods,reveal the evolution of microstructure,texture and inhibitor characteristics during rolling and annealing,and clarify the formation and development mechanism of secondary recrystallization texture.The main conclusions are as follows:(1)A inhibitor system with nano-sized composite precipitation constructed by designing the content of micro-alloy element,rolling and annealing process.And the special primary recrystallization texture is prepared by the parameter of rolling and annealing.The abnormal grain growth of Goss texture is induced by the inhibitor system and the primary recrystallization texture.(2)The content of Mn and Cu in the inhibitor system has an important influence on the secondary recrystallization of the Fe-Ga alloy sheet.The increase of Mn and Cu content can improve the texture of the primary recrystallization {111}<112>texture,as well as increase the quantity of precipitation,induce more perfect secondary recrystallization,and increase the magnetostriction coefficient.(3)The nano-sized composite inhibitors(MnS,Cu2S and(MnCu)S)mainly precipitated during hot rolling and normalization annealing provided strong pinning for the growth of primary grains.The abnormal grain growth of Goss grain is induced by the preferred coarsening of composite inhibitor during the slow heating process.The complete secondary recrystallization of Goss grains is induced by the primary recrystallization texture feature combined with the grain boundary movement characteristic is matched with the gradually regressed pinning force.(4)The primary recrystallization texture featured by strong {111}<112>and weak Goss texture is composed of large fraction of high energy grain boundary(HEGB),and the higher fraction of HEGB around Goss grain further promotes the secondary recrystallization of Goss grain.According to calculation of the relation between grain boundary mobility and misorientation angle,the HEGB favors the grain boundary migration.The non-Goss orientated grains are formed at the late stage of secondary recrystallization attributed to the reduction of the advantage at grain boundary mobility.In this study,Fe-Ga alloy sheet with high magnetostrictive property of secondary recrystallized Goss texture is prepared by the construction of inhibitor system,regulation of rolling and annealing process.In the future,it is necessary to improve the magnetostrictive properties of the Fe-Ga alloy sheet by optimizing the rolling and annealing process parameters. |
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