环向应力及热循环对N36管材氢化物应力再取向的影响研究

Effect of Hoop Stress and Thermal Cycling on Hydride Reorientation of N36 Alloy Cladding

采用高压釜渗氢、拉伸试验机进行氢化物应力再取向、金相显微镜和图像处理观察测量氢化物取向因子等方法,研究了环向应力和热循环次数对N36锆合金管材氢化物应力再取向的影响,获得了氢化物应力再取向分布规律。结果表明,F_N^(40°)随应力和热循环次数的增加而增大,最后趋于稳定,并且整个试样壁厚截面上的(F_N^(40°))均未超过0.5。在200~400℃上进行1个热循环周次时,氢化物应力再取向的应力阈值在80~95 MPa。

Metallographic microscope with image processing system was used to analyze the morphology and orientation factor of hydrides in N36 zirconium alloy tube. The effects of stress and time of thermal cycling on the reorientation of hydrides in N36 tubes specimen containing hydrogen were investigated. The results show that some of hydrides change from circumferential to the radial distribution and the hydride orientation factor（FN40°） increases with increasing the time of thermal cycling, and the hoop stress finally tends to be stable, then all the （FN40°） is less than 0.5. In once thermal cycling between 200℃ and 400℃, the stress-reorientation of hydrides happens under a hoop stress of 80 MPa-95 MPa.