【作者】 衡雪梅；

【导师】 唐正华；

【作者基本信息】 四川大学 ， 材料学， 2002， 硕士

【摘要】 随着核电在世界上日益广泛的应用，如何提高核电运行的安全性越来越受到人们的重视。同时，为了降低核电成本，高燃耗燃料元件也正在研制之中，这就对燃料包壳在高燃耗下防止破裂的能力提出了很高的要求。 针对锆合金的碘致应力腐蚀开裂，已经进行了大量的堆内及堆外模拟实验，结果表明，堆外模拟实验是一种安全、经济、有效的研究方法。 为了系统的研究应力腐蚀裂纹生长与应力强度因子、腐蚀介质浓度、温度及材料状况的依赖关系。本文建立了高温和强腐蚀介质(碘)环境下直流电压降测量裂纹长度的方法，对电位变化与裂纹长度之间的关系进行了定量标定。在350℃和400℃下确认了试样蠕变对DCPD测量方法的影响方式和影响程度。并针对不同成分(N36和N18)和不同热处理条件(去应力退火和再结晶退火)的锆合金。在不同的碘浓度(40℃、65℃和110℃)温度(300℃、350℃和400℃)下进行了应力腐蚀裂纹生长的监测实验。实验结果表明：实验温度、碘浓度以及材料状况对锆合金应力腐蚀裂纹生长均有明显影响。高倍下观察断口发现有准解理特征，在裂纹扩展最后阶段有塑性撕裂特征。更多还原

【Abstract】 The people have taken into account how to enhance the security of nuclear power more and more along with the application of nuclear powerincreasingly in the world. At the same time high powered fuel is being investigated in order to bring down the cost of nuclear power. This expounded the high require for the ability of fuel cladding to prevent cracking in high burn-up.To the iodine induced stress corrosion of zirconium alloys cladding , a lot of imitative tests of in-pile and out-of-pile had been done. The result showed out-of-pile imitative tests is a safe, economy and effect study method.In order to systematically study the dependency of stress corrosion crack growth on stress intensity factor , iodine concentration , temperature and materials condition , this paper had established the methodology of direct current potential drop (DCPD) measuring crack length in the high temperature and serious corrosion environment and did quantitative calibration to the relation between voltage transformation and crack length. It has been confirmed that creep of samples to an effect manner and degree on DCPD measurement methodology. This paper carried out control tests of stress corrosion crack growth at a different iodine concentration (40C,65C and 110C) and temperature (300C,350C and 400C) according with zirconium alloys of different composition (N36,N18)and heat-treatments (RXA, SRA).The results showed that temperature , iodine concentration and materials condition have obviously of affected on stress corrosion crack growth of zirconium alloys. According to the observed morphology on the fracture surface , the fracture surface had pseudo-cleavage feature and plastic tearing feature in the last stage of crack growth in high magnification.更多还原