Investigation of structure, phase composition, and mechanical properties of Zr-2.5% Nb alloy after ECAP

The analysis of the structure, phase composition, and mechanical properties of the industrial Zr-2.5% Nb alloy after severe plastic deformation by ECAP method were investigated. ECAP of the alloy leads to the formation of a grain-subgrain submicrocrystalline structure. The average size of the structural elements was 190 and 250 nm for the final temperature of ECAP of 350 °C, and 400 °C, respectively. ECA-pressing leads to a significant increase in the strength of the alloy while maintaining a sufficient reserve of plasticity and fully ductile dimple fracture. After ECAP, the alloy becomes single-phase (α-Zr). At temperatures above 570 °C, the precipitation of the particles of the second phase (β-Nb) was observed.