Grain Boundary Wetting by a Second Solid Phase in the Zr-Nb Alloys
Grain Boundary Wetting by a Second Solid Phase in the Zr-Nb Alloys
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DOI：
10.1007/s11665-012-0158-7
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发表时间：
2012-02
影响因子：
2.3
通讯作者：
B. Straumal;A. Gornakova;Yu. O. Kucheev;B. Baretzky;A. Nekrasov
中科院分区：
文献类型：
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作者：
B. Straumal;A. Gornakova;Yu. O. Kucheev;B. Baretzky;A. Nekrasov
锆铌合金作为核电站核燃料包壳的主要材料，在能源生产中发挥着重要作用。这些合金的形变热处理在Zr-Nb相图的（αZr）+（βZr，Nb）两相区进行。因此，（Zr）和（Nb）相的形态和相互排列起着极其重要的作用。含量为2.5，4，8重量%的二元Zr-Nb合金的显微组织在Zr-Nb相图的（αZr）+（βZr，Nb）两相区，在660 ~ 810 °C温度范围内研究了长时间退火（720 h）后的Nb。观察到（βZr，Nb）/（βZr，Nb）晶界被αZr相完全或不完全润湿。完全润湿的（βZr，Nb）/（βZr，Nb）晶界的比例从10%（660 °C）增加到接近Zr-Nb相图（850 °C）的（αZr）+（βZr，Nb）两相区的上边界的60%。（βZr，Nb）/（βZr，Nb）晶界开始被αZr相润湿的温度为Tws = 630 ± 10 °C。在所研究的样品中没有观察到被一层（βZr，Nb）相完全润湿的αZr/αZr晶界。
Zr-Nb alloys play the important role in the energy production being the main material for the cladding of nuclear fuel in the nuclear power plants. The thermo-mechanical treatment of these alloys proceeds in the (αZr) + (βZr, Nb) two-phase area of the Zr-Nb phase diagram. Therefore, the morphology and the mutual arrangement of the (Zr) and (Nb) phases play an extremely important role. The microstructure of binary Zr-Nb alloys with 2.5, 4, and 8 wt.% Nb after long anneals (720 h) was studied between 660 and 810 °C in the two-phase (αZr) + (βZr, Nb) area of the Zr-Nb phase diagram. (βZr, Nb)/(βZr, Nb) grain boundaries (GBs) completely or incompletely wetted by the αZr phase were observed. The portion of the completely wetted (βZr, Nb)/(βZr, Nb) GBs increases from 10% (at 660 °C) to 60% close to the upper border of the (αZr) + (βZr, Nb) two-phase area of the Zr-Nb phase diagram (850 °C). The temperature of the beginning of the GB wetting phase transition of (βZr, Nb)/(βZr, Nb) GBs by the αZr phase isTws= 630 ± 10 °C. The αZr/αZr GBs completely wetted by a layer of (βZr, Nb) phase were not observed in the studied samples.