添加S对Zr-Sn-Nb-Fe锆合金中第二相的影响

Effect of S Addition on the Second Phase Particles of Zr-Sn-Nb-Fe Zirconium Alloy

在Zr-0.70Sn-0.35Nb-0.30Fe（质量分数,%）合金成分基础上添加26-570μg/g的S制备成实验合金,用SEM、TEM及其配置的EDS研究了S含量对合金中第二相成分及晶体结构的影响。结果表明：不加S的重熔合金中的第二相均为密排六方结构的Zr（Nb,Fe）2,添加S以后合金中出现了正交结构的Zr3Fe第二相,并随着S含量的增加,Zr3Fe的数量也相应增多;添加的S含量为190μg/g时,合金中还出现了四方结构的Zr9S2第二相,并随着S含量的进一步增加,Zr9S2第二相的数量增多;同一成分合金中随第二相粒子尺寸的增大,第二相中的Nb/Fe比值逐渐降低。本研究制备的含S锆合金中,固溶在ɑ-Zr基体中的最大S含量在26-190μg/g之间,超过固溶含量的S以Zr9S2第二相析出,并没有进入其它第二相中。

To study the effect of S on the second phase particles（SPPs） of zirconium alloys, alloy samples were prepared by adding different contents of S（26~570 μg/g） into Zr-0.70Sn-0.35Nb-0.30Fe alloys. SEM and TEM with EDS were used to investigate the composition and crystalline structure of SPPs. The results show that in Zr-0.70Sn-0.35Nb-0.30Fe alloy, there exists Zr（Nb,Fe）2 SPPs with hexagonal close packed structure, while in the alloys containing S, orthogonal Zr3FeSPPs appear besides Zr（Nb,Fe）2 SPPs and the Zr3FeSPPs increase in amount with increasing S content. Zr9S2 SPPs occur when the S content reaches 190 μg/g, and also increase in amount with further increasing S content. The ratio of Nb/Fe decreases with the increase of SPPs＇ size in the same zirconium alloy. It is indicated that the S content dissolving in α-Zr matrix is between 26μg/g and 190μg/g for the alloys in this study and the excess S dissolving in α-Zr matrix is precipitated as Zr9S2 SPPs rather than entering into other SPPs.