铸造铝硅合金电导率和导热系数相关性的研究

Investigation on Relationship between Electrical Conductivity and Thermal Conductivity of Cast AluminumnAlloys

通过标准化铝锭生产、权威机构对电导率及导热系数的测定,研究了共计36种亚共晶、共晶、过共晶铸造铝硅合金电导率与导热系数的线性关系。结果表明铸造铝硅合金硅含量在7wt%~14wt%间变动时,铝硅合金的表观洛伦兹常数近似为1.88×10^(-8) WΩ/K^(2),也可由铝相体积百分比乘以低合金化铝合金的表观洛伦兹常数2.068×10^(-8) WΩ/K^(2)计算。晶格导热系数拟合值为35.2 W/(m·K),也可用低合金化铝和单晶硅的晶格导热系数(Al:16.1 W/m·K,Si:140W/(m·K))的体积加权平均值计算。工程应用可采用λ=5.52σ+35.2 W/(m·K)(电导率σ的单位为MS/m)计算铝硅合金的导热系数。

The linear relationship between electrical conductivity and thermal conductivity of 36 types of standardized cast Al-Si alloy ingots,which include hypoeutectic alloy,eutectic alloy and hypereutectic alloy,was studied by authoritative measuring of electrical conductivity and thermal conductivity.The results show that the apparent lorentz constant of the cast Al-Si alloy is approximately 1.88×10^(-8)WΩ/K^(2) when the Si content varies within the range from 7wt%to 14wt%.This value can be calculated by multiplying the apparent lorentz constant of low alloyed aluminum alloy(2.068×10^(-8)WΩ/K^(2))with the volume percentage of the aluminum phase.The fitted value of lattice thermal conductivity is 35.2 W/(m·K),which can be calculated by the volume weighted average value of lattice thermal conductivities of low alloyed aluminum and single crystal silicon(Al:16.1 W/(m·K))and Si:140 W/(m·K).The thermal conductivity of Al-Si alloy can be calculated byλ=5.52σ+35.2W/(m·K),the unit of electrical conductivity(σ)is MS/m.