Nb和Sn含量对锆合金氧化Pilling-Bedworth比影响的第一性原理研究

First-Principles Study on Effect of Nb and Sn Contents on Pilling-Bedworth Ratio for Oxidation of Zirconium Alloy

锆合金的耐蚀性能是影响其作为反应堆燃料包壳材料服役寿命的关键,Pilling-Bedworth(PB)比是反映锆合金腐蚀氧化过程的重要参数。采用第一性原理计算研究了Nb和Sn含量对锆合金氧化PB比的影响。首先分别计算了纯Zr、含Nb和Sn锆合金氧化成t-ZrO2与m-ZrO2的PB比;接着,研究了含Nb和Sn锆合金不同相结构含量对PB比的影响。结果表明:Nb的添加使锆合金的PB比减小,而Sn的添加使锆合金的PB比增大。最后,计算了商用Zr-Sn系Zr-4、Zr-Nb系M5、Zr-Sn-Nb系ZIRLO锆合金的PB比,发现M5合金的PB比低于Zr-4和ZIRLO合金。

Corrosion resistance of zirconium alloy is a key factor affecting its service life as a reactor fuel cladding material.The Pilling-Bedworth(PB)ratio is an important parameter reflecting the corrosion and oxidation process of zirconium alloy.The first-principles calculations were used to study the effects of Nb and Sn contents on the PB ratio for oxidation of zirconium alloys.First,the PB ratios of pure zirconium and zirconium alloys containing Nb and Sn oxidized into t-ZrO2 and m-ZrO2 were calculated respectively;then the effects of contents of different phase structures on the PB ratio of zirconium alloys containing Nb and Sn were investigated.The results showed that the addition of Nb reduced the PB ratio,while the addition of Sn increased the PB ratio of zirconium alloy.Finally,the PB ratios of commercial Zr-Sn series Zr-4,Zr-Nb series M5,Zr-Sn-Nb series ZIRLO zirconium alloys were calculated,and it was found that the PB ratio of M5 alloy was lower than those of Zr-4 and ZIRLO alloys.