In Situ Measurements of Grain Growth and Recrystallization by Laser Ultrasonics
Laser ultrasonics for metallurgy (LUMet) is an innovative sensor technology for in-situ measurement of microstructure evolution during thermomechanical processing. This unique sensor has been attached to a Gleeble 3500 thermomechanical simulator for dedicated laboratory studies during processing of steel, aluminum, magnesium and titanium samples. Advanced processing software has been developed for the measurement of grain size and texture evolution from laser ultrasonic signals. Results of austenite grain growth measurements in low carbon steels will be described to demonstrate the capabilities of the LUMet technique. Further, applications of the system to measure recrystallization of ferrite and austenite formation during intercritical annealing simulations of dual phase steels will be presented. The ability to rapidly acquire data both during a single test and for multiple conditions over a range of conditions from different samples has important implications on expediting process modelling and alloy design. Although certain limitations exist, the LUMet technique offers a very reliable characterization platform with a number of potential applications in metallurgical process engineering.
M. Militzer et al., "In Situ Measurements of Grain Growth and Recrystallization by Laser Ultrasonics", Materials Science Forum, Vol. 753, pp. 25-30, 2013