金属型铸造Al-9Si-xCu合金的组织及传热性能

Microstructure and Heat Transfer Performance of Al-9Si-x Cu Alloys for Permanent Mold Casting

本文采用水冷铜模铸造Al-9Si-xCu合金,分析了Cu含量对Al-9Si合金组织结构及传热性能的影响规律。结果表明,Al-9Si合金的导热性能随Cu含量的不同,呈现出不同的下降趋势。当Cu从0增至0.83%(质量分数)时,Cu元素以置换固溶体形式存在于基体,引起晶格畸变并导致自由电子散射几率增加,恶化导热性能,热导率从164.54 W/(m·K)降至149.02 W/(m·K);当Cu从0.83%增至2.00%(质量分数),Cu在基体已达饱和状态,以含Cu相存在,对热导率的影响相对较小;当Cu超过2.65%(质量分数)时,含Cu相数量减少,并进一步长大,其形貌、数量和分布上的变化有利于自由电子传输,一定程度减缓了合金热导率随Cu含量增加而下降的幅度。

The effect of Cu on the microstructure and heat transfer properties of Al-9Si alloys achieved by water-cooled copper mold casting has been investigated. The results show that the decreasing trend of thermal conductivity with various Cu contents is different. When the Cu content increases from 0 to 0.83%, the presence of Cu in the matrix as a replacement solid solution causes lattice distortion and increases the chance of free electron scattering, deteriorating the thermal conductivity from 164.54 W/(m·K) to 149.02 W/(m·K). As the Cu content increases from 0.83% to 2.00%, the added Cu reaches the saturated state and exists as a Cu-rich phase in the matrix, which has relatively little effect on the thermal conductivity. When the Cu content exceeds 2.65%, Cu-rich phases grow further and decrease in number. The changes in morphology, number and distribution of Cu-rich phases are conducive to free electron transport, thus slowing down the decrease in thermal conductivity with increasing Cu content.