Title screen

[References: p. 115 (3 tit.)]

The influence of intense plastic deformation on the formation of an ultrafine-grain state in Zr-1Nb alloy is considered, when the alloy contains secondary-phase particles in the volume and at the grain boundaries. Pressing with gradual temperature reduction in the range 973-573 K leads to solution of the secondary-phase particles and the formation of ultrafine grains and subgrains (mean size 0.25 ± 0.10 ?m) in the alloy structure. In pressing at room temperature with intermediate annealing for 1 h in the range 873-803 K, ultrafine grains and subgrains (mean size 0.45 ± 0.18 ?m) are formed in the alloy structure; the secondary-phase particles are retained. The formation of ultrafine-grain structure increases the strength and yield point of Zr-1Nb alloy by a factor of 1.5–2.0, with simultaneous localization of the plastic deformation and decrease in the uniform deformation; the deformation corresponding to failure is also reduced. The presence of secondary-phase particles in the ultrafine-grain structure, like the increase in grain size, prevents localization of the plastic deformation and increases the strain hardening.