Siliconizing behavior in non-grain oriented silicon steel after surface mechanical attrition treatment and cross shear rolling

Nanostructured surface layer was fabricated on a 3%(mass fraction) non-grain oriented silicon steel by means of surface mechanical attrition treatment(SMAT) and cross-shear rolling(CSR),and then a solid powder siliconizing treatment was carried out for the SMAT+CSR sample at 550~650 ℃ for 4 h.The microstructural evolution was examined by using transmission electron microscopy(TEM),scanning electron microscopy(SEM) and X-ray diffraction(XRD).Experimental results show that: equiaxed nanocrystallines with random orientations and about 10 nm in size were produced after the SMAT,which remain unchanged after the CSR.After the siliconizing treatment at 550~650 ℃ for 4 h,a compound layer forms on the SMAT+CSR sample,the layer thickness increases from 17 to 52 μm with the increment of the siliconizing temperature.The compound layer consists of Fe3Si and FeSi phases.