Variation of thermo physical properties of AI-Li (8090) quenched from the solid solution state (803 K) during heating (10 Kjmin) has been used to determine the temperatures at which the phase transformations take place. Transmission electron microscopic examinations were used to characterize the developed precipitates. It has been shown that the thermal properties can be used as a powerful tool for detecting phase transformations. Microstructural examinations after aging at 373, 438, 563 and 673 K revealed the formation of GP zones, 8'-(A13Li), TB-(A17Cu4Li) and T2-(AI6CuLi3) precipitates, respectively. 8'-particles and TB-(Al7Cu4Li) were observed to be nucleated intragranularly, whereas T r particles were observed to grow on the grain boundaries. © 2002 Elsevier Science B.V. All rights reserved.