“…The increase, then decrease in creep rate of Zr-2.5%Nb under uniaxial tension, respectively reported between 750 °C and 850 °C, and between 850°C and 950°C, was attributed by Shewfelt et al either to a change in grain size in the two-phase domain [Shewfelt at al 1984], or to a transformation-induced plasticity effect [Shewfelt & Lyall 1985]; nevertheless, no microstructural observations were reported to support the proposed mechanisms. A similar increase in creep rate was reported by [Hunt and Foote 1977, Alymov et al 1987, Fréchinet 2001, Kaddour 2004, Jailin et al 2020] close to the (α+β) / β phase boundary, i.e. in the upper part of the two-phase range, which will be denoted as "near-β" hereafter.…”