Zr-702 alloys are extensively utilized in the key corrosion-resistant structural materials of the chemical industry, which may be dramatically affected by hydrogen. In this study, Zr-702 alloys were hydrogenated via electrochemical hydrogen charging, and then the influence of charging time on their microstructure and mechanical properties was investigated. Circular and needle-like zirconium hydrides formed on the specimen surface were identified as γ-ZrH and δ-ZrH1.66 via x-ray diffraction (XRD) and transmission electron microscope (TEM) techniques. The phase transition was that supersaturated α phases transformed into δ and γ phases. The orientation relationships between γ-ZrH or δ-ZrH1.66 and α-Zr were (0 <InlineEquation ID="IEq1"> <EquationSource Format="TEX">$\overline{1}$</EquationSource> <EquationSource Format="MATHML"><math> <mover> <mn>1</mn> <mo>¯</mo> </mover> </math></EquationSource> </InlineEquation> 10)α || (11 <InlineEquation ID="IEq2"> <EquationSource Format="TEX">$\overline{1}$</EquationSource> <EquationSource Format="MATHML"><math> <mover> <mn>1</mn> <mo>¯</mo> </mover> </math></EquationSource> </InlineEquation>)γ with [2 <InlineEquation ID="IEq3"> <EquationSource Format="TEX">$\overline{1}\overline{1}$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mover> <mn>1</mn> <mo>¯</mo> </mover> <mover> <mn>1</mn> <mo>¯</mo> </mover> </mrow> </math></EquationSource> </InlineEquation> 0]α ||[<InlineEquation ID="IEq4"> <EquationSource Format="TEX">$\overline{1}$</EquationSource> <EquationSource Format="MATHML"><math> <mover> <mn>1</mn> <mo>¯</mo> </mover> </math></EquationSource> </InlineEquation> 10]γ and (0001)α || (11 <InlineEquation ID="IEq5"> <EquationSource Format="TEX">${\overline{\text{1}}}$</EquationSource> <EquationSource Format="MATHML"><math> <mover> <mtext>1</mtext> <mo>¯</mo> </mover> </math></EquationSource> </InlineEquation>)δ with [2 <InlineEquation ID="IEq6"> <EquationSource Format="TEX">$\overline{1}{\overline{\text{1}}}$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mover> <mn>1</mn> <mo>¯</mo> </mover> <mover> <mtext>1</mtext> <mo>¯</mo> </mover> </mrow> </math></EquationSource> </InlineEquation> 0]α ||[01 <InlineEquation ID="IEq7"> <EquationSource Format="TEX">$\overline{1}$</EquationSource> <EquationSource Format="MATHML"><math> <mover> <mn>1</mn> <mo>¯</mo> </mover> </math></EquationSource> </InlineEquation>]δ. Furthermore, hydrogen-induced cracks (HIC) were generated in the hydride layer. With the increase in charging time, the number of HIC occurrences and the hydride layer thickness increased. Meanwhile, the fracture elongation of samples decreased from 36.37 to 25.97%. The synergistic effect of zirconium hydride formation, HIC, and the zirconium hydride layer caused ductile deterioration of hydrogenated Zr-702 samples.

Hydride Formation and Hydrogen-Induced Cracking of Zr-702 Alloys after Surface Hydrogenation Treatment

期刊论文
发表日期：

2026年1月13日

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Yujie Bai,
Yao Wang,
Hui Chen,
Yuanxing Li

摘要

Zr-702 alloys are extensively utilized in the key corrosion-resistant structural materials of the chemical industry, which may be dramatically affected by hydrogen. In this study, Zr-702 alloys were hydrogenated via electrochemical hydrogen charging, and then the influence of charging time on their microstructure and mechanical properties was investigated. Circular and needle-like zirconium hydrides formed on the specimen surface were identified as γ-ZrH and δ-ZrH_1.66 via x-ray diffraction (XRD) and transmission electron microscope (TEM) techniques. The phase transition was that supersaturated α phases transformed into δ and γ phases. The orientation relationships between γ-ZrH or δ-ZrH_1.66 and α-Zr were (0 $\overline{1}$ $\bar{1}$ 10)_α || (11 $\overline{1}$ $\bar{1}$ )_γ with [2 $\overline{1}\overline{1}$ $\bar{1} \bar{1}$ 0]_α ||[ $\overline{1}$ $\bar{1}$ 10]_γ and (0001)_α || (11 ${\overline{\text{1}}}$ $\bar{1}$ )_δ with [2 $\overline{1}{\overline{\text{1}}}$ $\bar{1} \bar{1}$ 0]_α ||[01 $\overline{1}$ $\bar{1}$ ]_δ. Furthermore, hydrogen-induced cracks (HIC) were generated in the hydride layer. With the increase in charging time, the number of HIC occurrences and the hydride layer thickness increased. Meanwhile, the fracture elongation of samples decreased from 36.37 to 25.97%. The synergistic effect of zirconium hydride formation, HIC, and the zirconium hydride layer caused ductile deterioration of hydrogenated Zr-702 samples.