LASER FLASH THERMAL DIFFUSIVITY DETERMINATION PROCEDURE FOR HIGH-TEMPERATURE LIQUID METALS

ABSTRACT

A method is proposed for determining the thermal diffusivity of high-temperature liquid metals by levitating a small sample in microgravity conditions, melting it, and predicting Us response to a laser pulse. The solution is obtained by determining the initial temperature distribution in the thermal penetration depth created by the laser pulses and then solving the two-dimensional conduction equation in spherical coordinates for the cooling history of the droplet. The solution is obtained by assuming a short duration for the experiment. The correct diffusivity is obtained by minimizing the difference between the predicted and the experimentally obtained temperatures. The method is demonstrated for nickel, iron, and copper using analytical data, and is shown to have good accuracy.