Formation of the gamma phase by a peritectoid reaction in the zirconium-hydrogen system

Heat capacity of hydrogenated Zircaloy-2 and high Fe Zircaloy

“…There has been evidence [10] that supports the c-to d-phase transition around 460 K. From neutron diffraction measurements at high temperatures for Zr-2.5wt%Nb alloy, about 60% of c-phase, coexisting with d-phase at lower temperatures, transformed into dphase in a temperature range of 453-473 K [10]. On the other hand, c-to d-phase transition was detected at the higher temperature of 528 K for unalloyed Zr from DTA measurements [11]. Moreover, according to C p data of ZrD 1:01 (containing three phases a, d and c) by a scanning adiabatic calorimeter, a reversible and continuous anomaly was observed between 390 and 620 K, resulting from c !…”

Formation of a tetragonal phase hydride in Ti–Mo–H system

“…Two different mechanisms have been suggested for the formation of the ␥-phase Zr hydride. Mishra et al have suggested that the ␥-phase is a stable phase and formed at about 528 K through a peritectoid reaction of ␣ + ␦ ↔ ␥ [18]. Whereas, a metastable ␦ → ␥ transition involving a martensitic shear coupled with simultaneous hydrogen diffusion has been verified by Cassidy and Wayman [19].…”

Comments on the stability of zirconium hydride phases in Zircaloy

“…Northwood discussed this diagram in his 1983 review [2], in which he analyzes results from many authors, some of them proposing that the c-phase is an equilibrium phase, formed by a peritectoid reaction at about 255°C [3]. Northwood accepts however Beck's diagram and the metastability of the c-phase based upon experimental evidence.…”