Zr-Sn-Nb-Fe-V合金包壳管加工过程中第二相的演变

采用扫描电子显微镜（SEM）和透射电子显微镜（TEM）研究了Zr-0.2Sn-1.3Nb-0.2Fe-0.05V合金经热挤压、冷轧、中间退火包壳管坯以及经终轧及最终退火后成品管材第二相特征。结果表明，热挤压产生的β-Zr及第二相沿管坯轴向呈流线状分布，随着冷轧和退火的进行，亚稳相β-Zr发生分解，第二相逐渐均匀化，最终呈细小、均匀、弥散分布。合金成品管材第二相主要为BCC结构的β-Nb，含有少量FCC结构的Zr(NbFeV)₂。加工过程中析出相的平均直径变化不大，均小于100 nm。合金包壳管第二相尺寸分布与热处理过程中含Nb第二相溶解析出直接相关。

Second Phase Particle Evolution during Fabrication of Zr-Sn-Nb-Fe-V Alloy Cladding Tube

The microstructures of hot extruded tubes, cold rolled tubes and annealed tubes of Zr-0.2Sn-1.3Nb-0.2Fe-0.05V alloy cladding tubes were studied with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Results show that β-Zr and second phase particles (SPPs) tend to precipitate along the direction of deformation after hot extrusion. With processing and heat treatment for the alloy, β-Zr tends to be decomposed, and the size and distribution of SPPs become more and more homogeneous. β-Nb with BCC structure and Zr(NbFeV)₂ with FCC structure are found in the products. Average size of SPPs of every process stage doesn’t change much and is under 100 nm. The size and distribution of precipitates in Zr-Sn-Nb-Fe-V alloy cladding tube are closely related to decomposition and precipitation of SPPs containing Nb during heat treatment.