【摘要】 研究镍基高温合金GH706微观结构中晶格错配的非线性超声检测可行性。对经过固溶、稳定化、时效处理的合金进行金相、SEM、TEM检测,对不同热处理制度下GH706的平均晶粒尺寸进行定量提取,对共格界面类型进行定性分析;测量硬度,分析固溶强化及共格应变对硬度的影响;进行非线性超声检测,计算非线性系数,比较非线性系数、硬度、相界结构类型之间的关系。结果表明:时效强化为合金硬度主要影响因素时,非线性系数与硬度之间存在强相关性;非线性系数对晶界结构变化敏感,时效处理过程中的晶格错配是超声非线性的主要来源;非线性系数随着晶格错配程度的增加而增大,在非共格界面时达到峰值,随后逐渐下降。非线性超声检测技术可用于GH706晶格失配的定性无损评价。更多还原

【Abstract】 The effects of lattice mismatch on the nonlinear ultrasonic response of nickel-based superalloy GH706(Inconel 706) were examined. The nickel-based superalloy was heat treated under solution treatment, stabilizing treatment, and aging treatment conditions. Mean grain size, shape, and hardness were measured. Lattice mismatch of coherent interface were studied with transmission electron microscopy(TEM) images. The ultrasonic and nonlinear ultrasonic responses were detected and used for calculations. The results showed that there is a strong correlation between nonlinear coefficient and hardness when aging strengthening is the main influencing factor of alloy hardness. The nonlinear coefficient is sensitive to the change of grain boundary.Lattice mismatch during aging treatment is the main nonlinear source of ultrasonic. The nonlinear coefficient increases with the increase of lattice mismatch, reaches a peak at the occurrence of nonconforming interface, and then decreases gradually. The nonlinear ultrasonic technology can be used for non-destructive qualitative evaluation of lattice mismatch in GH706.更多还原