Perspective alloy of the Zr-Nb-Cr system for the new generation of nuclear reactors

Research of the Zr-Nb-Cr system alloys, promising for nuclear power engineering, with the aim of using them at operating temperatures of 500…600 ° C for a new generation of nuclear reactors have been carried out. The possibility of increasing the high temperature strength, heat resistance, and cast-technological properties of the most promising serial Zr-1Nb alloy due to alloying its with 1 wt.% Cr. The improvement of properties is explained by the dispersion hardening of the alloy by the high-temperature, strong intermetallide ZrCr₂. The high-temperature strength of the Zr-1Nb alloy can be increased by 30% in the temperature range 500…600 °C. The heat resistance of a promising alloy at a temperature of 500 °C exceeds the heat resistance of an industrial alloy Eh635 by 30…50% and is at the level of heat resistance of the Eh110 alloy at 20 hours exposure. The parabolic oxidation constants of the Zr-1Nb-1Cr alloy increase with increasing temperature and holding time, due to the formation of a dense scale of Cr₂O₃, ZrO₂ oxides, instead of the brittle scale Nb₂O₅, ZrO₂, which is characteristic for existing serial alloys Eh110, E635, E125.