This paper deals with the effect of air fraction in steam on the embrittlement of Zry-4 nuclear fuel cladding tubes exposed under steam–air atmospheres (air fractions of 10–100%) in the temperature range of 1273–1573 K. Ring compression tests were carried out in order to evaluate the embrittlement of fuel cladding. Furthermore, the microhardness of prior β-phase was measured and fractured surfaces were observed under scanning electron microscopy. The degree of the embrittlement is discussed against the results of metallographic and hydrogen analyses. The microstructure and the hydrogen pickup were substantially affected by nitride formation. Accelerated oxidation kinetics enhanced shrinking of the prior β-region. The enhanced hydrogen absorption resulted in the increased microhardness of prior β-phase. The degree of the fuel cladding embrittlement, expressed by the plastic strain at failure and the maximum load, correlated well with the microhardness and the thickness of prior β-phase.

中文翻译：

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蒸汽中空气分数对 1273–1573 K 氧化的 Zry-4 燃料包壳脆化的影响

本文讨论了在 1273-1573 K 温度范围内蒸汽中空气分数对暴露在蒸汽-空气气氛（空气分数为 10-100%）下的 Zry-4 核燃料包壳管脆化的影响。 环压缩试验为了评估燃料包壳的脆化而进行的。此外，测量了先前β相的显微硬度，并在扫描电子显微镜下观察了断裂表面。脆化程度根据金相和氢分析的结果进行讨论。微观结构和吸氢显着受氮化物形成的影响。加速氧化动力学增强了先前 β 区域的收缩。增强的吸氢导致先前β相的显微硬度增加。燃料包壳脆化程度，