The thermo-mechanical behavior of Zircaloy-4 claddings under simulated post-DNB RIA conditions was investigated. Around twenty experiments were performed in simulated post-DNB conditions, i.e. creep ballooning tests with heating rates greater than 1000 °C/s. Two different levels of pressure of 7 and 11 bar were tested for temperatures of interest ranging from 840 °C to 1020 °C. A complex creep behavior was highlighted in this range of temperature. It appears very well correlated to the phase content present within the material during fast thermal transients. Tests with low thermal transients were also performed and evidence a strong impact of the heating rate on the thermo-mechanical properties of the claddings.

研究了在模拟的DNB RIA条件下Zircaloy-4覆层的热机械行为。在模拟的DNB后条件下进行了大约20个实验，即加热速率大于1000°C / s的蠕变膨胀试验。在840°C至1020°C的温度范围内测试了7和11 bar两种不同的压力水平。在此温度范围内，复杂的蠕变行为被突出显示。它似乎与快速热瞬变过程中材料中存在的相含量非常相关。还进行了具有低热瞬态的测试，并证明了加热速率对熔覆层的热机械性能的强烈影响。