Tensile properties of zr−1 wt.% Nb alloy

• Published in: Journal of nuclear materials Vol. 78; no. 1; pp. 49 - 57
• Main Authors: Thorpe, W.R., Smith, I.O.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 1978
• ISSN: 0022-3115; 1873-4820
• DOI: 10.1016/0022-3115(78)90503-2

The tensile properties of Zr−1 wt% Nb alloy were determined in the temperature interval 295 to 773 K. A phenomenological description of the tensile behaviour of the alloy is derived in terms of the Holloman equation and the activation area and enthalpy for deformation. The strain-hardening exponent of the Holloman equation reaches a maximum value of $ ̃ 0.23 for deformation at 573 K and this is associated with the occurrence of dynamic stain-ageing. The apparent activation energy for this process is 51 ± 15 kcal/mole which is in agreement with that for lattice diffusion of oxygen in α-Zr. The strain-rate sensitivity, activation area and enthalpy values obtained for the deformation of the alloy compare favourably with those reported for Zr− O alloys. The occurrence of an athermal region in the deformation at 6̃00 K is rationalised in terms of the superposition of two mechanisms: (i) dynamic strain-ageing due to Snoek ordering of solute atom pairs and (ii) thermally activated overcoming of oxygen atom clusters.