Effect of Initial Goss Texture Sharpness on Texture Evolution and Magnetic Properties of Ultra-thin Grain-oriented Electrical Steel

In this study, high- and low-grade grain-oriented electrical steels were used as the initial materials to produce 0.08-mm-thick sheet with one-step cold-rolling method. Electron backscattering diffraction analysis technique and X-ray diffraction texture analysis technique were adopted to investigate the effect of initial Goss texture sharpness on texture evolution and magnetic properties of ultra-thin grain-oriented electrical steel. The results showed that primary recrystal- lization and secondary recrystallization were the main processes that occurred during annealing. The induced factors for secondary recrystallization of two grades samples were not Consistent. The high-grade samples presented texture induction mechanism, while the low-grade samples revealed strong surface-energy induction mechanism. The initial Goss texture sharpness had a great impact on texture evolution and magnetic properties of ultra-thin grain-oriented electrical steel. The Goss texture component formed after primary recrystallization was stronger, and better magnetic properties were obtained at low frequencies. For low-grade samples, secondary recrystallization enhanced the intensity of Goss texture, and both grain size and texture contributed to better high-frequency magnetic properties after secondary recrystallization. By controlling the annealing process, the magnetic properties of low-grade products could be significantly improved, thus achieving conversion from low-grade to high-grade products.

Secondary recrystallization of Goss texture in magnetostrictive Fe–Ga-based sheets

To avoid the unfavorable effect of precipitates on magnetic properties,low addition of 0.16 wt%NbC was employed in Fe_(82.5)Ga_(17.5)alloy,and 0.27 mm sheets were successfully prepared by a rolling process.Strong Goss texture was obtained in Fe-Ga sheets by two-stage annealing process.The sulfur annealing in quartz ampoules was made to produce the preferred growth of Goss texture,with a 51%increase in the observed saturation magnetostriction,from 87×10^(-6)in the Ar-annealed sheets to 132×10^(-6)in the S-annealed sheets.However,large amounts of S-rich and Nb-rich precipitates were formed in the S-annealed sheets.High-temperature annealing of the S-annealed sheets at 1,200℃under a flow hydrogenargon atmosphere could effectively eliminate the precipitates and promote the selective growth of(110)grains due to the low surface energy.Large grains(~2 cm)of secondary recrystallization were achieved in the final annealed sheets,with the maximum average saturation magnetostriction of 180×10^(-6).

Single Goss grain growth by isothermal annealing in rolled Fe–Al–Ga–Nb C sheets

The(Fe_(82)Al_(13.5)Ga_(4.5))_(99.9)(NbC)_(0.1) sheets with strong Goss texture and large magnetostriction were prepared by rolling and isothermal annealing processes.Single Goss grain growth was observed in sheets undergoing isothermal annealing at 1050 ℃ for 1 h using Ar as protecting gas.With annealing time increasing to 8 h at1050℃,a largest magnetostriction of 154×10^(-6) is obtained in sheet and a large λ_(//)(the maximum magnetostriction with magnetic field parallel to rolling direction)of 160×10^(-6) along the rolling direction is also observed.The fact that a λ_(//) of 160×10^(-6) along RD can be achieved with only 4.5 at% Ga in the Fe-18 at%(Al,Ga) sheet is of practical importance.Compared with previous studies in Fe-Al and Fe-Ga sheets,this paper provides a more efficient approach to prepare strong Goss textured sheets.In this way,a slow continuous heating process,sulfur-induced surface energy control and high-temperature annealing above 1200 ℃ are no more necessary.It shows a good prospect for industrial production of high-performance magnetostrictive alloy sheets.

Evolution of Texture in Grain Oriented Silicon Steels

Goss texture or （110）[100] crystallographic orientation of the grains is typical grain structure of grain oriented silicon steel used for transformer. This type of texture is one of the most important parameters determining the magnetic properties of the laminated steel plates. The furination and growth of Goss texture in three steel samples are investigated. Two of them are prepared under laboratory conditions and one under industrial conditions. The em- phasis is put on the effects of hot lamination temperature and time, primary and secondary recrystallization temperatures during cold lamination on developing of the Goss texture in correlation with other texture components. Also in all steel processing stages, the influence of the chemical composition on the occurrence of Goss texture is examined.

Dislocation ordering and texture strengthening of naturally aged Al-Cu-Mg alloy

Stability of grain structure,dislocation ordering and strengthening mechanisms of the naturally aged AlCu-Mg alloy after solution treatment are investigated by using optical microscope(OM),scanning electron microscope(SEM),electron back-scattered diffraction(EBSD),X-ray diffraction(XRD) and transmission electron microscope(TEM).Results show that {100}<001>,{100}<110>,{110}<110> and {110}<001>slip systems can be activated after solution treatment,which can promote the formation of {110}<001>Goss texture.The combination effect of T-Al_(20)Cu_(2) Mn_(3) phase and Goss-oriented grains with large Taylor factor makes the solution-treated alloys display excellent stability of grain structure.The enhanced yield strength of the alloy is ascribed to grain-refine strengthening,dispersed particles strengthening,dislocation strengthening and texture strengthening.The coarsening of the second phase is responsible for softening of the alloy after annealing at 400 ℃+solution treatment at 475 ℃.