含双边轴向裂纹N18锆合金薄壁管的蠕变裂纹扩展行为研究

通过对含双边轴向裂纹管(DEAT)试样及其加载装置进行设计,基于能量等效和载荷分离原理获得了DEAT试样的能量率回路积分(C*积分)表达式,从而建立了含轴向裂纹薄壁管的蠕变裂纹扩展速率测试方法。基于此方法,采用DEAT试样完成了N18锆合金薄壁管在350℃不同载荷水平下的蠕变裂纹扩展试验。结果表明,蠕变载荷会显著影响N18锆合金的蠕变裂纹扩展速率;蠕变裂纹扩展可分为稳态扩展和快速扩展2个阶段;蠕变裂纹扩展速率(da/dt)与C*积分存在良好的幂律关系,可用于预测N18锆合金管蠕变裂纹扩展行为。

Creep Crack Growth Behavior of N18 Zircaloy Thin-Walled Tubes with Double Edged Axial-Notched Cracks

Through the design of double edged axial-notched tube (DEAT) specimen and fixture, the expression of C* integral of DEAT specimen was obtained based on the principles of energy equivalent and load separation. A test method for the creep crack growth rate of thin-walled tubes with axial cracks has been established. The creep crack growth tests of N18 zircaloy thin-walled tubes at different load levels at 350℃ are carried out by using DEAT specimens. The results show that the creep load will significantly affect the creep crack growth rate of N18 zircaloy; the creep crack growth can be divided into two stages: steady state expansion and rapid expansion; the creep crack growth rate (da/dt) and C* integral have a good power-law relationship, and it can be used to predict the creep crack growth behavior of N18 zircaloy.