발간논문

Home > KJMM 논문 > 발간논문

Compositional dependence of the magnetic properties such as the saturation magnetization and the magnetic anisotropy energy were analysed using the three magnetic subnetwork mean field model and these results were compared to the radial distribution functions obtained from X-ray diffraction spectra and the hyperfine field distribution from Mossbauer spectroscopies. The ratio of the ferromagnetic Fe-subnetwork to the antiferromagnetic Fe-subnetwork and the spin value of Fe varied with the composition and all of Fe-subnetworks are coupled antiparallel to the Tb-subnetwork. Also, it was found that the hyperfine field at Fe nuclear is affected significantly by the conduction electron polarization due to the magnetic mean field near the center Fe atom as well as by the core electron polarization.

keyword :

The application of hot -dip galvannealed steel sheet was studied in order to improve corrosion-resistance of the Zn-coated steel sheet. As spot welding is widely used for assembling automotive bodies, hot - dip galvannealed steel sheet is desired to have a good spot weldability as well as formability. This report is discussing the spot weldability, especially the factors which give the influence on the tensile shear strength and the cross-tensile strength of the weld. The results are summarized as follow : (1) Expulsion had no effect on the tensile shear strength but been observed on the cross tensile strength of the specimen. (2) Welding current and weld time were measured by experiment and were explained by a weldability lobe.

keyword :