Effect of inhomogeneous composition on the thermal conductivity of an Al alloy during the precipitation-hardening process

Precipitation hardening of Al alloys is an essential aging process for industrial applications demanding lightweight and high-mechanical strength materials. However, this process drastically reduces the thermal conductivity of the Al alloy owing to the formation of intermetallic precipitates. Because the growth of the intermetallic precipitates is a complicated process involving the diffusion of alloying elements as well as phase transformation, the prediction of the thermal conductivity during the precipitation process has not been accomplished. Herein, an accurate prediction method for the effective thermal conductivity of Al alloys during the precipitation process is presented. Interestingly, the study finds that the inhomogeneous distribution of the composition in the Al solid solution generates a considerably inhomogeneous distribution of the thermal conductivity around the precipitates; consequently, the accuracy of our prediction is 30% higher than that in previous studies.