中文摘要：

采用500℃，10．3MPa过热蒸汽腐蚀方法，研究了热处理对Zr-4合金耐疖状腐蚀性能的影响。试样经过600，820和1000℃不同热处理后，耐疖状腐蚀性能明显不同。提高Fe，Cr合金元素在α-Zr中过饱和固溶含量，可以明显改善耐疖状腐蚀性能，第二相的大小不是决定的因素。用高分辨扫描电镜观察了氧化膜的内表面形貌和断口形貌，研究了耐疖状腐蚀性能与氧化膜显微组织之间的关系。从疖状腐蚀斑的成核与长大，热处理会引起Fe和Cr合金元素在α-Zr中过饱和固溶含量的变化，以及从氧化膜生长的各向异性与α-Zr中合金元素过饱和固溶含量的关系出发，讨论了热处理影响耐疖状腐蚀性能的机制。

英文摘要：

The effects of heat treatments on the nodular corrosion resistance of Zircaloy-4 have been investigated in the super-heat steam of 500 ℃ and 10.3 MPa by autoclave tests. It is found that the nodular corrosion resistances are obviously different for the specimens heat treated at 600 ℃, 820 ℃ and 1000 ℃, respectively. The key factors improving the nodular corrosion resistance are the supersaturated solid solution contents of Fe and Cr alloying elements in α-Zr matrix, but the size of the second phase particles. In order to study the relationship between the nodular corrosion resistance and the microstructure of oxide films, the morphologies of inner surface and fracture surface of oxide films were examined by high resolution scanning electron microscopy. According to the nucleation and growth of nodule corrosive spots, the effect mechanism of heat treatments on nodular corrosion resistance in Zircaloy-4 was discussed. It is shown that the supersaturated solid solution contents of alloying elements in α-Zr matrix could be changed by different heat treatments, and the growth of oxide films is anisotropic on the crystallographic plane with different orientations.