连续流变挤压耐热Al-Sc-Zr-Fe合金组织协同细化与强化机制

Heat-resistant aluminum alloy conductors are widely used worldwide and becoming the developing direction of global electric aluminum production. In Europe, the United States and Japan, 70% of conductor wires are aluminum conductors, while the portion is less than 3% in China. At present, the main disadvantage of Al-Sc-Zr alloy heat-resistance wire is the high price. Fe phases in aluminum alloys were proved to be harmful to mechanical properties due to the needle plate shape, and it is very difficult to get rid of Fe from Al alloys. Therefore the project puts forward a method which combines the Fe phase refinement by continuous rheo-extrusion with the collaborative grain refinement by Sc, Zr phase and Fe phase, so as to enhance the performance of wires, turn Fe into treasure and reduce the Sc content and the cost of wires..The study content includes: cooling/shear coupling mechanisms during continuous rheo-extrusion forming process; mechanism of collaborative refinement by Sc, Zr phase and Fe phase; mechanism of cooperative reinforcement by Sc, Zr phase and Fe phase in Al-Sc-Zr-Fe alloys; effects of process parameters on the microstructure and properties of aluminum alloy conductive rods; preparation of high performance and low cost Al-Sc-Zr-Fe heat-resistant aluminum alloy conductors. The proposed project is a synthesis of heat transfer, hydromechanics, solidification, metal forming, metal and electric engineering, and will provide theory guidance for future studies on short preparation process of high performance heat-resistance electrical aluminum materials.

耐热铝合金导线以其载流量大、安全性高的优势在世界各国架空导线中获得越来越广泛的应用，成为国际电工铝材的发展方向。欧美与日本等铝导线用量占总导线的70%以上，而我国不到3%。目前研制的Al-Sc-Zr合金耐热导线的成本高，铝合金中针片状Fe相降低了导线的性能，除Fe难度较大。因此本项目提出将连续流变挤压对Fe相细化与Sc、Zr、Fe协同细化相结合，提高导线性能，将Fe变废为宝，同时降低Sc含量和导线成本。.研究内容包括：连续流变挤压成形过程中冷却/剪切耦合机制；含Sc、Zr相与含Fe相的协同细化机理；Al-Sc-Zr-Fe合金中各相对材料的协同强化机制；工艺参数对铝合金导电杆组织性能的影响；制备高性能、低成本的Al-Sc-Zr-Fe耐热铝合金导线。在传热学、流体力学、金属凝固学、塑性加工学、金属学、电工学等领域开展研究，为高性能耐热电工铝材的短流程加工技术提供理论指导。

项目针对耐热铝合金导线成本高，以及铝合金中针片状Fe相损害性能严重、除Fe难度大的问题，提出将连续流变挤压对Fe相细化与Sc、Zr、Fe协同细化相结合，将Fe变废为宝，综合提高导线性能，同时降低Sc含量和导线成本。.圆满完成了任务书中的研究计划，获得主要成果如下：.（1）阐明了连续流变挤压过程中纳米Al3Fe相的形成机理及其对合金力学性能的影响；.（2）揭示了热作用下纳米Al3Fe相的演化机理及其对力学性能的影响；.（3）分析了第二相硬质粒子尺寸对连续动态再结晶的影响，并获得了临界粒子尺寸的计算模型；.（4）获得了冷轧变形对连续流变挤压Al-1Fe (wt. %)合金力学性能的影响，并分析了强化机理；.（5）揭示了累积连续挤压变形过程中Al-1Fe (wt. %)合金组织演化机理；.（6）制备出了综合性能优良的、低成本的Al-0.05Sc-0.1Zr-0.5Fe (wt. %)合金耐热导线，综合性能优于国际电工委IEC62004-2007的标准值。.发表标有资助号的SCI收录的论文10篇；获得授权国家发明专利2件；以第一完成人获辽宁省技术发明一等奖；项目负责人入选国家“万人计划”科技创新领军人才、科技部中青年科技创新领军人才，培养研究生毕业5名；参加国内外学术会议7次，担任大会副主席和分会主席5次，作邀请报告4次。.项目科学意义与创新点如下：.（1）建立了冷却/剪切耦合条件下第二相细化方法与理论，采用了连续流变挤压成形和Sc、Zr对含Fe相进行协同细化，细化效果显著；.（2）利用含Fe相的耐热和强化作用减少了Sc的添加量，省去了难度较大的除Fe工艺，将Fe变废为宝，降低了合金成本；.（3）采用自己开发的连续流变挤压机制备出了综合性能优良的、低成本的耐热铝合金导线。.