Zr-2.5Nb合金经β相水淬、冷轧变形及580℃,50 h退火处理,在静态高压釜中进行500℃/10.3 MPa的过热蒸汽腐蚀实验.HRTEM观测表明,580℃,50 h退火处理的锆合金析出了颗粒细小(<100 nm)的β-Nb第二相,其数量较多,分布较均匀.β-Nb相的氧化速率比锆合金基体缓慢,在氧化过程中首先生成NbO_2,呈现晶态和非晶态的混合组织,然后转变成非晶态占主导的氧化物,最后流失到腐蚀介质中. The Zr-2.5Nb alloy was subjected to water quenching, cold rolling deformation and annealing at 580 ℃ for 50 h, and the superheated steam corrosion test was carried out at 500 ℃ / 10.3 MPa in a static autoclave.The results of HRTEM showed that annealing at 580 ℃ for 50 h The treated zirconium alloy precipitated the second phase of β-Nb with small size (<100 nm), which was more in quantity and more evenly distributed.The oxidation rate of β-Nb phase was slower than that of zirconium alloy, and the first phase of NbO_2 , Showing a mixed crystalline and amorphous structure, and then transformed into amorphous dominant oxide, and finally lost to the corrosive medium.