亚共晶Al-Si合金的微观组织调控及共晶Si对Al基体晶格导电机制的影响

Hypoeutectic Al-Si alloy becomes important materials for the preparation of overhead transmission lines due to its excellent electrical conductivity and thermal conductivity, etc. However, for this aluminum alloy, good electrical conductivity and excellent mechanical properties are contradictory and this limits its application obviously. In this project, hypoeutectic Al-Si alloys were selected as the main research subjects and through the method of experiments combined with theoretical calculation, research work was carried through purification of Al matrix and modification of eutectic Si morphology two aspects. The doping law among transition elements in the multiple borides and the regularity of correlation about the eutectic Si electronic structure and the matrix lattice potential field will be studied in detail, revealing the melt composite boron treatment reaction mechanism and the influencing mechanism of eutectic Si morphology evolution on electrical conductivity of the alloy. Based on this, the intrinsic relationship between electrical conductivity and mechanical property will be analyzed deeply, and a theoretical model for the correlation of electrical conductivity and mechanical properties was established. Thus, a new composite boron treatment and technology processing will be put forward to purify the Al matrix and modify the eutectic Si morphology, reducing the damage to lattice periodic arrangement of Al matrix on the premise of guarantee the excellent mechanical properties of the alloy. Provide a new idea and theoretical basis for the preparation of a new aluminum alloy with high strength and good electrical conductivity.

亚共晶Al-Si合金因其良好的导电、导热等特性成为制备架空输电线的重要材料。但该类合金的导电性和力学性能很难兼顾，限制了其更广泛的应用。本项目以亚共晶Al-Si合金为研究对象，实验与理论计算相结合，拟从净化Al基体和改善共晶Si两方面开展研究；探讨硼化处理过程中多元硼化物过渡族金属元素间的相互掺杂规律以及共晶Si电子结构与基体晶格势场的相关性，揭示熔体复合硼化反应机制和共晶Si形貌演变对合金导电率的影响，并以此深入研究合金导电性与力学性能的内在关联性，建立合金导电性-力学性能相关性理论模型。基于上述研究，利用熔体复合硼化及加工处理新技术，净化Al基体并调控共晶Si，在保证合金优异力学性能的前提下最大程度地减小基体晶格畸变以提高其导电率，为制备一种高强、高导的铝合金材料提供新思路和理论基础。

亚共晶Al-Si合金因其良好的导电、导热等特性成为制备架空输电线的重要材料，但该类合金的导电性和力学性能很难兼顾，限制了其更广泛的应用。本项目以亚共晶Al-Si合金为研究对象，从净化Al基体和改善共晶Si两方面开展了系列研究工作：首先，探讨了硼化处理过程中多元硼化物过渡族金属元素间的相互掺杂规律并揭示了熔体复合硼化反应机制，在此基础上提出微量过渡族金属元素辅助硼化处理的新工艺，大大提高了硼化处理效率从而最大程度的净化Al基体；其次，通过Sr变质、热处理、热挤压形变处理等手段改善共晶Si形貌、颗粒尺寸、分布状态等，分析共晶Si形貌演变对合金导电率的影响机制，并以此深入研究合金导电性与力学性能的内在关联性，建立合金导电性-力学性能相关性理论模型。最终成功净化了Al基体并调控共晶Si，在保证合金优异力学性能的前提下最大程度地减小基体晶格畸变而提高了其导电性，制备了一种高强、高导的Al-Si-Mg-Fe-Cu合金材料，为导电铝合金材料的制备提供新思路和理论基础。