Design and preparation of aluminum alloy with high thermal conductivity based on CALPHAD and first-principles calculation

摘要

To obtain the aluminum alloy with high thermal and mechanical properties,the effects of alloying elements and the second phases on the thermal conductivity of Al alloys were investigated by CALPHAD and first-principles calculation,respectively.The properties of the second phases,including Young's modulus,Poisson's ratio and minimum thermal conductivity,were systematically studied.Results show that the ranking order of the effects of the alloying elements on the thermal conductivity is Mg>Cu>Fe>Si,and for Al-12Si alloys,the mathematical model of the relationship between the alloying elements and the thermal conductivity can be expressed as λ=ax^(2)-bx+c when the second phase precipitates in the matrix.All kinds of ternary phases of Al-Fe-Si have higher deformation resistance,rigidity,theoretical hardness,Debye temperature and thermal conductivity than the other phases which possibly exist in the Al-12Si alloys.Based on the guidance of CALPHAD and first-principles calculation,the optimized chemical composition of Al alloy with high conductivity is Al-11.5Si-0.4Fe-0.2Mg(wt.%)with a thermal conductivity of 137.50 W·m^(-1)·K^(-1)and a hardness of 81.3 HBW.