In the binary Zr-H, Ti-H systems, there are three common hydride phases, namely γ-, δ-, and ε-hydride, with different ratios of H to Zr/Ti atoms. Among them, the relative stability of γ-hydride remains controversial, although it has been observed in many studies. In this study, we demonstrate that γ-hydride is the only stable hydride phase in high purity Zr and commercial purity Ti, using electrolytically loaded hydrogen and ex-situ synchrotron x-ray diffraction. Further, in-situ synchrotron heating/cooling experiments were conducted with hydrided pure Zr sample demonstrating the co-existence of γ- and δ-hydride phase, from a furnace cooling heat treatment followed by three days room temperature aging. It is shown that during heating γ-hydride dissolved first, while δ-hydride remained stable at temperatures up to 280°C, followed by dissolution of δ-hydride until all hydrogen was in solution. Under subsequent slow cooling, δ-hydride precipitated first, followed by a slow formation of γ-hydride when temperatures were below 210°C, which continued during a subsequent 60 hours aging at room temperature. The phase stability when hydride forms as precipitates in Zr is therefore determined to be δ-hydride as the high temperature phase, and γ-hydride as the low temperature phase. The microstructural characteristics of γ-hydride in Zr and Ti were studied by electron microscopy. The observed co-existence of γ- and δ-hydride as well as change from δ to γ during long term room temperature aging in the TEM confirmed the synchrotron data.

在二元Zr-H，Ti-H系统中，存在三种常见的氢化物相，即γ-，δ-和ε-氢化物，且H与Zr / Ti原子的比例不同。其中，尽管在许多研究中都发现了γ-氢化物的相对稳定性仍存在争议。在这项研究中，我们证明了γ-氢化物是高纯度Z​​r和商业纯度Ti中唯一稳定的氢化物相，使用电解负载的氢和非原位同步加速器X射线衍射。此外，用氢化纯Zr样品进行了原位同步加速器加热/冷却实验，该样品证明了γ-和δ-氢化物相的共存，其来自炉冷却热处理，然后进行了三天的室温老化。结果表明，在加热过程中，γ-氢化物首先溶解，而δ-氢化物在高达280°C的温度下保持稳定，然后溶解δ-氢化物，直到所有氢溶解。在随后的缓慢冷却下，首先氢化出δ-氢化物，然后在温度低于210°C时缓慢形成γ-氢化物，并在随后的60小时室温下持续老化。因此，可以确定氢化物在Zr中以沉淀形式形成时的相稳定性为：δ-氢化物为高温相，γ-氢化物为低温相。用电子显微镜研究了Zr和Ti中γ-氢化物的微观结构特征。观察到的γ-和δ-氢化物的共存，以及在TEM中长期室温老化过程中从δ到γ的变化，证实了同步加速器数据。随后，当温度低于210°C时，缓慢生成γ-氢化物，并在随后的60小时室温下持续老化。因此，可以确定氢化物在Zr中以沉淀形式形成时的相稳定性为：δ-氢化物为高温相，γ-氢化物为低温相。用电子显微镜研究了Zr和Ti中γ-氢化物的微观结构特征。观察到的γ-和δ-氢化物的共存，以及在TEM中长期室温老化过程中从δ到γ的变化，证实了同步加速器数据。随后，当温度低于210°C时，缓慢生成γ-氢化物，并在随后的60小时室温下持续老化。因此，可以确定氢化物在Zr中以沉淀形式形成时的相稳定性为：δ-氢化物为高温相，γ-氢化物为低温相。用电子显微镜研究了Zr和Ti中γ-氢化物的微观结构特征。观察到的γ-和δ-氢化物的共存，以及在TEM中长期室温老化过程中从δ到γ的变化，证实了同步加速器数据。γ-氢化物为低温相。用电子显微镜研究了Zr和Ti中γ-氢化物的微观结构特征。观察到的γ-和δ-氢化物的共存，以及在TEM中长期室温老化过程中从δ到γ的变化，证实了同步加速器数据。γ-氢化物为低温相。用电子显微镜研究了Zr和Ti中γ-氢化物的微观结构特征。TEM中观察到的γ-和δ-氢化物共存以及在长期室温老化过程中从δ变为γ证实了同步加速器数据。