中文摘要：

采用静态高压釜腐蚀试验研究了Zr-0．8Sn-0．35Nb-0．4Fe-0．1Cr-xBi（x=0．1，0．3和0．5，质量分数，％）合金在400℃／10．3MPa过热蒸汽中的腐蚀行为；并用TEM、EDS和SEM观察分析了合金和腐蚀后氧化膜的显微组织。结果表明，在Zr-0．8Sn-0。35Nb-0．4Fe-0．1Cr合金中添加0．1％，0.3％和0．5％的铋对其在400℃过热蒸汽中的耐腐蚀性能都有较大改善作用，但随着铋含量的增加，其改善作用减弱；在Zr-0．8Sn-0．35Nb-0．4Fe-0．1Cr合金中添加0．1％铋后，合金中只有Zr（Fe，Cr，Nb）。一种第二相；添加0．3％铋后，有Zr（Fe，Cr，Nb）2和Zr-Fe-Sn-Bi两种第二相析出；添加0．5％铋后，有Zr（Fe，Cr，Nb）2，Zr-Fe-Sn-Bi和Zr-Fe-Cr-NtySn-Bi三种第二相析出；Zr-0．8Sn-0．35Nb-0．4Fe-0．1Cr合金中添加适量铋会促进原来固溶的锡以第二相析出。以上结果说明Zr-0．8Sn-0．35Nb-0．4Fe-0．1Cr-xBi合金在580℃时a-Zr基体中可固溶不少于0．1％的铋，这对改善合金的耐腐蚀性能是有利的，但含铋和锡第二相的析出则使合金的耐腐蚀性能下降。

英文摘要：

An autoclave was employed to investigate the effect of Bi contents on the corrosion resistance of Zr-0. 8Sn- 0. 35Nb-0. 4Fe-0. 1Cr-ccBi （x=0. 1%--0. 5%, mass fraction） alloys in superheated steam at 400 ℃ and 10. 3 MPa. The microstructures of the alloys and oxide films on the corroded specimens were observed by TEM and SEM, respectively. The results show that （0. 1%--0. 5 ~） Bi addition can improve the corrosion resistance of the Zr-0. 8Sn- 0. 35Nb-0. 4Fe-0. 1Cr alloy, but the degree of the improvement effect decreases with the increase of Bi contents. Only Zr（Fe,Cr,Nb）2 second phase particles （SPPs） were detected in the alloy with 0.1% Bi; Zr（Fe,Cr,Nb）2 and Zr-Fe- Sn-Bi SPPs were detected in the alloy with 0. 3 % Bi. Zr（Fe, Cr, Nb）2, Zr-Fe-Sn-Bi and Zr-Fe-Cr-Nb-Sn-Bi SPPs were detected in the alloy with 0.5 % Bi. This implies that the Bi addition promotes the precipitation of Sn as the SPPs and the solid solubility of Bi in a-Zr matrix of Zr-0. 8Sn-0. 35Nb-0. 4Fe-0. 1Cr-xBi alloys is not less than 0. 1% at 580 ℃. From the above results, it can be concluded that the Bi as solid solution in a-Zr matrix can improve the corrosion resistance, however, the precipitation of SPPs containing Bi and Sn is deleterious to the corrosion resistance.