镍基单晶合金气冷叶片模拟试样的蠕变性能研究

对带孔和不带孔的某第二代镍基单晶合金平板试样进行了蠕变性能试验研究与有限元对比计算.高温蠕变试验表明, 平板试样的晶体取向和是否开孔对蠕变寿命有明显的影响.气膜孔导致蠕变寿命的降低, 对[001]取向的影响大于[111]取向.在高温低应力条件下, [001]取向的蠕变性能要优于[111]取向.有限元分析结果表明, 气膜孔改变了试样中的应力分布, 在孔附近产生了高应力, 导致模拟试验蠕变寿命的降低.有限元计算蠕变持久寿命与试验结果吻合, 说明采用基于分切应力的蠕变持久寿命计算模型是合理的. 

Study on the creep behavior of model specimens of nickel-based single crystal air-cooled blades

Plate specimens were used to model turbine blades with cooling holes.Experimental and numerical study on the creep behavior of a second generation nickel-based single crystal alloy has been performed with these model specimens.The results of creep test at high temperature show that crystallographic orientations and cooling holes have noticeable influence on the creep life.Compared with that of the specimen without cooling holes,the creep life of specimen with cooling holes is lower for both and orientations.The cooling holes have larger influence on the creep life of orientation than that of orientation.The creep behavior under high temperature and low stress conditions of orientation is better than that of orientation.The finite element analysis(FEA) results reveal that the cooling holes change the stress distribution in the specimen and cause stress concentration near the holes,which results in the decrease of creep life.As the creep life obtained from FEA is accordant to the experimental result,it is reasonable to calculate the creep life using the simulation model based on the resolved slip stress.