针对涡轮发动机涡轮叶片复杂应力状态下的时效变形问题,以涡轮叶片材料Waspaloy镍基合金为研究对象,开展Waspaloy镍基合金时效处理,完成时效态Waspaloy镍基合金600、700和750℃准静态高温力学拉伸 试验.利用Ludwik和Hollomon经验公式预测Waspaloy镍基合金高温塑性段流变应力,引入平均误差(the mean error,Er)和均方根误差(root mean square error,RMSE)评价流变应力的预测准确度.结果表明,时效处理后合金的硬度得到有效提升,而其塑性性能有所降低.Waspaloy镍基合金的抗拉强度和延伸率在600～750 ℃区间范围内与加载温度呈负相关关系.Ludwik模型较Hollomon模型有更高的流变应力预测精度,而在高温高应变区域Ludwik模型预测流变应力仍存在较大误差.在Ludwik模型的基础上引入指数项,修正后的Ludwik模型能更好地预测Waspaloy镍基合金高温塑性段的流变应力.
Abstract
Aiming at the aging deformation of turbine blades in turbine engines under complex stress,Waspaloy nickel-based alloy was taken as the research object to carry out aging treatment and complete quasi-static high temperature mechanical tensile tests of Waspaloy nickel-based alloy at 600,700 and 750 ℃.The flow stress of Waspaloy nickel-based alloy at high temperature plastic section was predicted by Ludwik and Hollomon empirical formulas,and the mean error(Er)and root mean square error(RMSE)were introduced to evaluate the accuracy of the flow stress prediction.The results show that the hardness of Waspaloy nickel-based alloy is improved effectively after aging treatment,but its plastic properties are reduced.The tensile strength and elongation of Waspaloy nickel-based alloy are negatively correlated with the loading temperature in the range of 600～750 ℃.Ludwik model owns higher accuracy than Hollomon model in flow stress prediction,but there is a still large error in flow stress prediction in high temperature and high strain region.Based on the Ludwik model,the exponential term is introduced,and the modified Ludwik model have a better prediction result in the flow stress of Waspaloy nickel-based alloy at high temperature plastic section.
关键词
Waspaloy镍基合金/时效处理/流变应力/本构模型
Key words
Waspaloy nickel-based alloy/aging treatment/flow stress/constitutive model
维普
万方数据