The effects of Si

Fe

Mn

Sr and T2 heat treatment on the microstructure and properties of high thermal conductivity aluminum alloy were investigated by metallographic microscope

scanning electron microscope

laser thermal conductivity meter and digital conductivity meter. The results indicate that the increase of Si

Fe and Mn contents has a negative effect on the thermal conductivity and electric conductivity of aluminum alloy

since the lamellar eutectic silicon

the long needle-like β-Fe phase and the lamellar Al-Mn phase hindering energy transfer dominated by electron. The solution of Si leads to the decrease of thermal conductivity and electric conductivity

while T2 heat treatment can reduce the adverse effect of lattice distortion and improve the thermal conductivity of the alloy. The eutectic silicon phase can be effectively refined by Sr. When the content of Sr is 0.03%

thermal conductivity of the aluminum alloy reaches the maximum of 200.7 W/（m·K） and the conductivity is 26.53 MS/m. The Al-6 Si-0.8 Fe-0.0075 Sr alloy was applied to heat sink die castings

where the as-cast thermal conductivity reaches over 173.43 W/（m·K）

and up to 212.86 W/（m·K） after T2 heat treatment.