500℃过热蒸汽中Zr-4基体晶粒形貌和取向对应力状态的影响

Effect of Grain Morphology and Orientation of Zr-4 Matrix on Stress State at 500℃Superheated Steam

为了研究Zr-4合金在500℃条件下晶粒取向与晶粒形貌对合金基体应力分布状态的影响,采用有限元方法构建3种不同晶粒形貌的模型,以(1120)取向晶粒占比为变量,施加氧化膜生成时作用于基体的应力,对Zr-4合金基体晶粒变形进行模拟。计算结果表明:晶粒形貌与不同取向晶粒占比对基体晶粒内部应力分布的影响有明显规律。随着(1120)取向晶粒占比(14.6%~85.4%)的增加,Zr-4合金基体中的应力集中现象更加明显,应力集中将促使Zr-4合金在腐蚀中加速失效;晶粒形貌越接近等轴晶,模型中应力分布越均匀,应力值趋于减小,有利于提高合金的耐腐蚀性能。

In order to study the influence of the grain orientation and grain morphology of Zr-4 on the stress distribution of the alloy matrix at 500℃,the grain deformation of the Zr-4 has been simulated by the finite element method according to three different grain morphology models with a variable of the different(1120)oriented grains’proportion.And the stress that acts on the matrix when the oxide film is formed is applied to the simulation as the load.The simulated results show that the grain morphology and the proportion of oriented grains have obvious influence on the internal stress distribution of the matrix grains.With the increase of the proportion of(1120)oriented grains(14.6%~85.4%),the stress concentration in the Zr-4 matrix becomes more obvious,and the stress concentration will promote the failure of the Zr-4 during corrosion.The more likely to the equiaxed crystal of the grain,the more homogeneous the stress distribution is in the model,and the less of the stress value is,which is beneficial to improve the corrosion resistance of the alloy.