Photopyroelectric Measurement of the Thermal Diffusivity of Recrystallized High Purity Aluminum

Abstract Thermal diffusivity measurements on high purity (99.99% pure) aluminum samples are reported, using chirped and sinusoidally-modulated laser excitation and photopyroelectric detection of the thermal wave response. The results are found to be dependent on the degree of recrystallization of the specimen: for cold-rolled aluminum, the thermal diffusivity is measured to be α = 3.10 × 10−5 m2/s, which rises to 3.88 × 10−5 m2/s for fully recrystallized samples, and then falls to 3.53 × 10−5 m2/s for samples exhibiting the initial stages of grain growth.