Speaker
Description
The precise control of grain size during hot deformation is paramount for the mechanical integrity of aerospace-grade nickel-base superalloys. This study investigates the recrystallization behavior of Nickel-base alloy 718 by employing classical hot deformation experiments in combination with a novel experimental setup: a DSI Gleeble 3800 thermal-mechanical simulator integrated with a Laser Ultrasound system. This approach allows for the in-situ measurement of microstructural changes — specifically grain growth and recrystallization — during the actual deformation and following heat treatment.
Isothermal compression tests were conducted at different temperatures, partly with subsequent holding at temperature. The Laser Ultrasound system utilizes a pulsed laser to generate ultrasonic waves and a laser interferometer to detect them. By measuring the ultrasonic attenuation in real-time, the recrystallization and grain growth was quantified as it occurred.
Results indicate that hot deformation with Laser Ultrasound provides a very good correlation with post-mortem EBSD (Electron Backscatter Diffraction) analysis, particularly in identifying the necessary temperatures and holding times required for meta-dynamic recrystallization. This approach supports the optimization of thermomechanical processing routes for nickel base superalloys used in aerospace applications.
| Speaker Company/University | voestalpine BÖHLER Edelstahl GmbH & Co KG |
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