Role of activation energies of individual phases in two-phase range on constitutive equation of Zr-2.5Nb-0.5Cu alloy
(1. Department of Metallurgical and Materials Engineering, Indian Institute of Technology,
Roorkee-247667, Uttarakhand, India;
2. Nuclear Fuel Complex Limited, Hyderabad-501301, India;
3. Materials Science Division, Bhabha Atomic Research Center, Mumbai-40085, India;
4. Department of Mechanical Engineering, Insitute of Engineering and Technology,
GLA Uinversity, Mathura-281406, Uttar Pradesh, India)
Roorkee-247667, Uttarakhand, India;
2. Nuclear Fuel Complex Limited, Hyderabad-501301, India;
3. Materials Science Division, Bhabha Atomic Research Center, Mumbai-40085, India;
4. Department of Mechanical Engineering, Insitute of Engineering and Technology,
GLA Uinversity, Mathura-281406, Uttar Pradesh, India)
Abstract: Dominant phase during hot deformation in the two-phase region of Zr-2.5Nb-0.5Cu (ZNC) alloy was studied using activation energy calculation of individual phases. Thermo-mechanical compression tests were performed on a two-phase ZNC alloy in the temperature range of 700-925 °C and strain rate range of 10-2-10 s-1. Flow stress data of the single phase were extrapolated in the two-phase range to calculate flow stress data of individual phases. Activation energies of individual phases were then calculated using calculated flow stress data in the two-phase range. Comparison of activation energies revealed that α phase is the dominant phase (deformation controlling phase) in the two-phase range. Constitutive equations were also developed on the basis of the deformation temperature range (or according to phases present) using a sine-hyperbolic type constitutive equation. The statistical analysis revealed that the constitutive equation developed for a particular phase showed good agreement with the experimental results in terms of correlation coefficient (R) and average absolute relative error (AARE).
Key words: Zr-2.5Nb-0.5Cu alloy; hot deformation; activation energy; constitutive equation; two-phase material