Influence of the minor alloying on microstructure and mechanical properties of Zr-Nb alloy

This study investigates the influence of minor alloying elements on the phase stability, microstructure, and mechanical properties of Zr-Nb alloys through integrated first-principles calculations and experimental approaches. Special quasirandom structure (SQS) modeling revealed that Mo doping significantly can stabilize the β phase by inducing strong electron interactions with the Zr/Nb matrix, whereas V, Ta, and Hf additions failed to achieve comparable stabilization. The Zr-Nb-X alloys were prepared by powder metallurgy. It demonstrated that alloys with Mo addition exhibited enhanced β phase proportion, suppressed continuous grain-boundary α-phase formation, and refined grain structures, leading to simultaneous improvements in dynamic strength and ductility. In contrast, V doping promoted grain coarsening and compromised dynamic plasticity despite strengthening effects, while Hf and Ta additions induced specific microstructural deterioration modes, including blocky α-phase aggregation along grain boundary and transgranular cracking. The electrons interaction, phase distribution, and fracture behavior were systematically elucidated, highlighting Mo as the optimal microalloying candidate for balancing β stability and mechanical performance. These findings provide a computational-experimental framework for designing Zr alloys with tailored microstructures and superior load-bearing capabilities under dynamic conditions.