Effect of Al addition on the mechanical property and irradiation resistance of NbMoZr-based medium-entropy alloys

Abstract

In this work, the Nb50Mo30Zr20 and Al5Nb50Mo30Zr15 alloys are successfully fabricated and the samples are irradiated by 5 MeV Xe+ ions at 350 °C and 750 °C. Room temperature compression results show that the addition of Al can effectively increase the compressive yield strength from ∼ 1288 MPa in NbMoZr alloy to ∼ 1703 MPa in AlNbMoZr alloy. The increase in strength is attributed to the solid solution strengthening, second phase strengthening and dendrite refinement strengthening due to the minor Al additions. After irradiation at 350 °C and 750 °C, the HCP-structured Zr phases precipitate in ternary NbMoZr alloy. In contrast, with the addition of Al atoms, the dendritic matrix of AlNbMoZr alloy can still maintain the BCC structure after irradiation, which exhibit a higher phase stability than NbMoZr alloy. Moreover, the Al suppress the growth of Xe bubbles and decrease the dislocation loops in AlNbMoZr alloy, as compared with those in the Al-free NbMoZr alloy. The relevant results can provide theoretical guidance for developing high-performance metals used in the field of advanced nuclear fuels.