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...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,E_(r))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。展开更多
Scanning electron microscopy（SEM） and energy dispersive X-ray analysis（EDAX） were used to study the microstructure,microsegregation, and fluid flow tendency of the superalloy Waspaloy in the mushy zone,which had b...Scanning electron microscopy（SEM） and energy dispersive X-ray analysis（EDAX） were used to study the microstructure,microsegregation, and fluid flow tendency of the superalloy Waspaloy in the mushy zone,which had been solidified at different cooling rates. The investigation was accompanied with the calculation of Rayleigh numbers.It is found that Ti is the main segregating element and the content of Ti is the highest in the final liquid at the cooling rates of 3-6℃/min.The eta phase（η） precipitate presented in the residual liquid at the cooling rates higher than 6℃/min is responsible for the fluctuations in the curves of Ti content.The dendrite arm spacing is found to markedly decrease with the increase of cooling rate.The maximum relative Rayleigh number occurs at 10-20℃below the liquidus temperature at a cooling rate of 1℃/min,where the mushy zone is most unstable and fluid flow is most prone to occur.展开更多
文摘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,E_(r))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。
基金supported by the school fund of Nanjing University of Information Science and Technol ogy
文摘Scanning electron microscopy（SEM） and energy dispersive X-ray analysis（EDAX） were used to study the microstructure,microsegregation, and fluid flow tendency of the superalloy Waspaloy in the mushy zone,which had been solidified at different cooling rates. The investigation was accompanied with the calculation of Rayleigh numbers.It is found that Ti is the main segregating element and the content of Ti is the highest in the final liquid at the cooling rates of 3-6℃/min.The eta phase（η） precipitate presented in the residual liquid at the cooling rates higher than 6℃/min is responsible for the fluctuations in the curves of Ti content.The dendrite arm spacing is found to markedly decrease with the increase of cooling rate.The maximum relative Rayleigh number occurs at 10-20℃below the liquidus temperature at a cooling rate of 1℃/min,where the mushy zone is most unstable and fluid flow is most prone to occur.
