【摘要】 对不同固溶温度的GH4169合金试样,进行了微观组织形貌观察,提取了晶粒尺寸、形状特征参数。采用纵波回波法和共线穿透法进行超声检测和非线性超声检测,计算合金的超声特性参数。提取的超声特性参数包括:衰减系数、声速、相对非线性系数、背散射信号(位于一次底波和二次底波之间)经验模态分解后固有模态函数的平均功率和波形指数。超声-微观结构参数对比分析的结果表明,通过衰减系数、声速、非线性系数可有效识别相变,衰减系数对晶粒尺寸波动敏感,随晶粒粗化而增大;所提取的固有模态函数平均功率和波形维数都可以对晶粒尺寸进行评价,但尚难以用于表征晶粒纵横比。更多还原

【Abstract】 In this work the effects of solution temperature on microstructure and ultrasonic response of nickelbased super alloy GH4169 were examined.Characteristic parameters of grain size and shape were measured.Longitudinal wave echo method and collinear penetration method were used to test the samples,and the ultrasonic parameters,such as velocity,attenuation coefficient,and relative nonlinear coefficient,were calculated.The power and waveform index of intrinsic mode functions(IMFs)of backscattered signals dealt with empirical mode decomposition were calculated.Comparison between ultrasonic and microstructure data shows that the attenuation coefficient,velocity,and nonlinear coefficient could be used to make an effective identification of phase transition.The attenuation coefficient increased with the increase of grain size and was strongly sensitive to the change of grain size.Both power and waveform index of IMFs of backscattered signals could be used to estimate grain size,but they were difficult to characterize the axial ratio of grain.更多还原