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11种不同组织状态的Zr—2.5Nb合金板材和退火的Zr—4合金板材,在400℃高压水蒸汽中腐蚀350天,在345℃饱和水和300℃加压水中腐蚀800天。大部分样品的增重—时间曲线上存在着速率转折,转折后的增重规律可以近似地用指数方程△W=Kt~n来表示;n值随组织状态而变。一些抗腐蚀性较好的样品在300℃水中腐蚀800天仍未达到转折;文中提出了用高温短时增重数据外推低温长时增重数据的方法。根据外推结果,经880℃水淬并在500℃时效的Zr—2.5N_b合金,在300℃加压水中腐蚀30年时有最好的抗腐蚀性能。
Eleven kinds of Zr-2.5Nb alloy sheets and annealed Zr-4 alloy sheets with different microstructure were etched in high-pressure steam at 400 ° C for 350 days and corroded in saturated water at 345 ° C and pressurized water at 300 ° C for 800 days. Most of the samples have a rate transition on the weight-time curve, and the law of weight gain after the transition can be approximated by the exponential equation ΔW = Kt ~ n; the value of n changes with the state of the tissue. Some samples with good corrosion resistance have not yet reached the turning point in water corrosion at 300 ℃ for 800 days. In the paper, a new method of extrapolating long-term weight gain data with low temperature and high temperature is proposed in this paper. According to the extrapolation results, the Zr-2.5N_b alloy, which was quenched at 880 ° C and aged at 500 ° C, had the best corrosion resistance at 30 ° C for 30 years in pressurized water.