Experimental and theoretical study of the microstructure evolution and thermal-physical properties of hypereutectic Al-Fe alloys

A systematic investigation was undertaken to analyze the microstructure and thermal-physical properties of hypereutectic Al-xFe alloys. With increasing Fe content, the Al13Fe4 phase undergoes a morphological shift from needle-like to lamellar-like. The coarse Al13Fe4 negatively affects the thermal conductivity (TC), resulting in a decrease from 200.1 to 84.5 W/(m/K) of TC as the Fe content rises from 2 to 12 wt%. Simultaneously, the thermal expansion coefficient (CTE) decreases. At 100 degrees C, Al-12Fe has a CTE of 17.6 x 10-6/K. Additionally, first-principles calculations were used to understand the intrinsic properties of the Al13Fe4. Using the quasi-harmonic approximation (QHA), the linear CTE of Al13Fe4 at 100 degrees C was calculated to be 9.88 x 10-6/K. By integrating experiments and theoretical calculations, the generalized effective medium theory (GEMT) and a modified Turner model were employed to quantitatively describe the correlation between the microstructural evolution of Al-xFe alloys and their TC/CTE.