TY - JOUR
T1 - Multi-scale Microstructural Characterization and Precipitation Mechanism of Hydrides in Zr-2.5Nb Alloy Pressure Tube
AU - Li, Bo
AU - Cui, Changxing
AU - Li, Yanchao
AU - Wang, Hui
AU - Sun, Shuo
AU - Sun, Huanzheng
AU - Feng, Zheng
AU - Zhang, Wen
AU - Zhang, Guojun
N1 - Publisher Copyright:
© The Minerals, Metals & Materials Society 2026.
PY - 2026/4
Y1 - 2026/4
N2 - The integrity and performance of Zr-2.5Nb alloy pressure tubes in nuclear reactors are significantly influenced by the behavior of hydrides within the material. A comprehensive understanding of the hydride distribution, orientation relationship, and precipitation mechanism is crucial for predicting and mitigating potential degradation in these critical components. This study presents a multi-scale characterization approach, integrating scanning electron microscopy, electron backscatter diffraction, and transmission electron microscopy, to investigate the mesoscale, microscale, and atomic-scale features of hydrides in Zr-2.5Nb alloy pressure tubes. The results reveal that hydrides predominantly form along α/α grain boundaries and α/β phase boundaries, with minimal intragranular presence. Distinct crystallographic orientation relationships between interfacial and intragranular hydrides and the α-Zr matrix are identified. Interfacial hydrides (γ-ZrH, δ-ZrH1.66, and ε-ZrH2) exhibit a strong hereditary orientation relationship with the α-Zr matrix, characterized by <112¯0>α//<110>γ//<110>δ//<111>ε and {0001}α//{111}γ//{111}δ//{101}ε. Intragranular hydrides maintain the relationship of <112¯0>α//<110>γ//<110>δ//<110>ε and {0001}α//{200}γ//{200}δ//{200}ε. High-resolution transmission electron microscopy observations uncovered a continuous slip of Shockley partial dislocations within the α-matrix, originating from 60° mixed-type perfect dislocations on each basal plane. This slip, coupled with an atomic shuffle mechanism, facilitates the B-type phase transition, leading to the precipitation of δ-ZrH1.66 with a face-centered cubic structure.
AB - The integrity and performance of Zr-2.5Nb alloy pressure tubes in nuclear reactors are significantly influenced by the behavior of hydrides within the material. A comprehensive understanding of the hydride distribution, orientation relationship, and precipitation mechanism is crucial for predicting and mitigating potential degradation in these critical components. This study presents a multi-scale characterization approach, integrating scanning electron microscopy, electron backscatter diffraction, and transmission electron microscopy, to investigate the mesoscale, microscale, and atomic-scale features of hydrides in Zr-2.5Nb alloy pressure tubes. The results reveal that hydrides predominantly form along α/α grain boundaries and α/β phase boundaries, with minimal intragranular presence. Distinct crystallographic orientation relationships between interfacial and intragranular hydrides and the α-Zr matrix are identified. Interfacial hydrides (γ-ZrH, δ-ZrH1.66, and ε-ZrH2) exhibit a strong hereditary orientation relationship with the α-Zr matrix, characterized by <112¯0>α//<110>γ//<110>δ//<111>ε and {0001}α//{111}γ//{111}δ//{101}ε. Intragranular hydrides maintain the relationship of <112¯0>α//<110>γ//<110>δ//<110>ε and {0001}α//{200}γ//{200}δ//{200}ε. High-resolution transmission electron microscopy observations uncovered a continuous slip of Shockley partial dislocations within the α-matrix, originating from 60° mixed-type perfect dislocations on each basal plane. This slip, coupled with an atomic shuffle mechanism, facilitates the B-type phase transition, leading to the precipitation of δ-ZrH1.66 with a face-centered cubic structure.
UR - https://www.scopus.com/pages/publications/105030626387
U2 - 10.1007/s11837-025-07672-w
DO - 10.1007/s11837-025-07672-w
M3 - 文章
AN - SCOPUS:105030626387
SN - 1047-4838
VL - 78
SP - 3408
EP - 3423
JO - JOM
JF - JOM
IS - 4
ER -