N36锆合金管棒材第二相研究

Study on Second Phase Particles in N36 Alloy Claddings and Bars

利用扫描电子显微镜(SEM)和透射电子显微镜(TEM)及其能谱仪(EDS)附件,研究了N36锆合金成品管棒材中的第二相粒度、分布、成分及结构。结果表明,N36合金管材和棒材中的第二相平均尺寸差别不大,但二者的形貌及分布有较明显的差别。衍射及能谱分析表明,N36管棒材中的第二相主要为六方相的C14型Zr(Nb,Fe)_2 Laves相及少量的β-Nb,与文献报道的基本一致,但棒材中Laves相的Nb含量较低,晶格常数也较小。研究还表明,管材α-Zr基体中Nb含量与其固溶度较接近,质量百分数约为0.3%~0.4%,低于一般认为的0.6%。

Second phase particles(SPPs) in N36 zirconium alloy claddings and bars was studied by SEM and TEM equipped with EDS. The result showed that SPPs in the claddings and the bars nearly have the same average diameter, but have different morphology and distribution. Zr(Nb,Fe)_2 Laves phase and a few of β-Nb phase precipitates were detected both in N36 alloy claddings and bars by diffraction and EDS analysis, but Laves phase in the bars had lower Nb content and smaller crystal lattice than that in the claddings. This study also illuminated that Nb content in α-Zr matrix for the cladding approaches to the solubility limit which appears equal to 0.3 wt^0.4 wt%, which is much lower than the usually assumed value of 0.6 wt%.