Abstract Recrystallization and grain growth following hot deformation of an L605 cobalt superalloy was measured in real time using laser ultrasonics. Ex-situ microstructure characterization of quenched samples in combination with double hit tests was used to evaluate the potentials and limitations of the laser ultrasonic method for these in-situ measurements. Significant grain refinement occurs during recrystallization and was recorded with the ultrasonic attenuation using a calibration previously developed for Co superalloys including L605. At higher deformation temperatures complete recrystallization takes place and the recrystallized grain size is independent of temperature. At lower deformation temperatures, recrystallization remains incomplete which can be deduced from the apparently larger grain size obtained from attenuation measurements than in the cases of complete recrystallization. The present approach has the potential to accelerate the development of thermomechanical processing paths through real time measurements of microstructure evolution in Co superalloys as well as other metals and alloys.

中文翻译：

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L605钴高温合金再结晶和晶粒长大的激光超声测量

摘要 使用激光超声实时测量 L605 钴高温合金热变形后的再结晶和晶粒长大。淬火样品的非原位微观结构表征与双击测试相结合，用于评估激光超声方法在这些原位测量中的潜力和局限性。在再结晶过程中发生显着的晶粒细化，并使用先前为包括 L605 在内的 Co 超合金开发的校准通过超声波衰减记录。在较高的变形温度下，会发生完全再结晶，再结晶的晶粒尺寸与温度无关。在较低的变形温度下，再结晶仍然不完全，这可以从衰减测量获得的晶粒尺寸明显大于完全再结晶的情况下推断出来。本方法有可能通过实时测量 Co 高温合金以及其他金属和合金的微观结构演变来加速热机械加工路径的发展。