| Two kinds of the specimens made of Zr-Sn-Nb experimental alloys were investigated for their corrosion behaviors and mechanical properties after some different thermo-mechanical treatments including the final heat treatments as stress-relived (SR) at 470℃ and recrystallized (RX) at 520℃ for 2.5 hours, respectively. The corrosion tests were carried out in the autoclaves containing 360℃ water, 400℃ steam and 360℃ aqueous LiOH(70 ppm) solution. Microstructures of the tested specimens were analyzed using an optical microscopy and TEM, and those of their oxides using small angle XRD method. All of the tested specimens showed higher corrosion rates in the steam than in the water or the aqueous LiOH solution. The specimens having lower Nb and Sn content showed a little better corrosion resistance in all the environments than those having higher Nb and Sn content. It was found out that SR specimens had higher t-ZrO₂ fraction to m-ZrO₂ showing better corrosion resistance than that of RX ones as well as the SR ones had more hardness, tensile strength, and creep resistance than the RX ones. |
|
