Structure and Corrosion-Mechanical Properties of the Surface Layers of Steels after Laser Alloying

We perform the thermodynamic analysis of the solubility of alloying elements and stability of possible secondary phases of chromium and chromium-nickel steels in the components of the Li₁₇Pb₈₃ eutectic heat carrier and reveal the negative effect of the lead melt on the long-term strength and plasticity of the major part of these steels. It is proposed to improve the stability of the characteristics of structural steels promising for nuclear and thermonuclear power engineering by the laser alloying (modification) of the surfaces with Zr, Nb, or Si and B. By analyzing the changes in the microhardness, structure, and thermoelectromotive force of the corresponding coatings on holding in the eutectic melt at 350 or 500°C for 10⁴ h, it is shown that the procedure of laser alloying may result in the formation of layers with long-term protective action.