Abstract The influence of diffusive Nb redistribution on the microstructure and Volta potential of U-5.5Nb alloys thermally aged at 400 °C for durations between 1 h and 100 h was investigated and their surfaces were examined post-corrosion using various microscopy techniques. The results demonstrated that Nb-depleted lamellae resulting from Nb redistribution have the lowest Volta potential in the microstructure and are extremely sensitive to pitting, as demonstrated by immersion experiments and potentiometric polarization tests. However, the pitting potential of the aged alloys (205.2 ± 3.9 mV) did not change with the content of Nb-depleted lamellae.

中文翻译：

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扩散Nb再分布对U-5.5Nb合金点蚀敏感性的影响

摘要 研究了扩散 Nb 再分布对 U-5.5Nb 合金在 400 °C 下热时效 1 小时至 100 小时的微观结构和伏特电势的影响，并使用各种显微镜技术检查了腐蚀后的表面。结果表明，Nb 再分布导致的 Nb 耗尽层片在微观结构中具有最低的 Volta 电位，并且对点蚀极其敏感，如浸没实验和电位极化测试所证明的那样。然而，时效合金的点蚀电位 (205.2 ± 3.9 mV) 不随 Nb 贫化片晶的含量而变化。