Zr-0.2Cu-xNb合金的显微组织及腐蚀行为

对Zr-0.2Cu-x Nb(质量分数x=0.2,0.5,1.0,2.5)合金进行真空β相油淬、冷轧及退火处理,并在静态高压釜中进行过热蒸汽腐蚀试验,最后采用扫描电镜和透射电镜研究了合金及其腐蚀生成的氧化膜的显微组织。结果表明,随着Nb含量的增加,Zr-0.2Cu-x Nb合金中Zr2Cu第二相的数量逐渐减少,而β-Zr第二相数量逐渐增加;合金中尺寸较小的Zr2Cu第二相对耐腐蚀性能有利;β-Zr第二相在氧化过程中会促进氧化膜微裂纹的产生,降低合金的耐腐蚀性能。Zr-0.2Cu-x Nb合金中Nb含量接近其在α-Zr中最大固溶度时,合金具有最优的耐腐蚀性能。

Microstructure and Corrosion Behavior of Zr-0.2Cu-xNb Alloys

Zr-0.2Cu-xNb(x=0.2, 0.5, 1.0, 2.5) alloys were prepared by vacuum β-phase oil quenching, cold-rolling deformation and annealing. The superheated steam corrosion test was carried out in a static autoclave. The microstructure of the alloy and the oxide film formed by corrosion was studied by scanning electron microscopy and transmission electron microscopy. The results show that with the increasing of Nb content, the number of Zr2Cu phases in Zr-0.2Cu-xNb alloys decreases gradually, while the number of β-Zr phases increases gradually. The second phase of Zr2 Cu with small size is beneficial to corrosion resistance. The β-Zr second phase promotes the generation of micro-cracks in the oxide film during oxidation and reduces the corrosion resistance of the alloy. When the Nb content in Zr-0.2Cu-xNb alloy is close to its maximum solid solubility in α-Zr, the alloy has the best corrosion resistance.