Mn元素合金化对8076铝合金线材组织与性能的影响

发布时间：2018-08-29 16:01

【摘要】：8000系列铝合金导线凭借其高电导率高强度高抗蠕变性能，以及良好的经济价值，已受到越来越多的重视，在国内外得到了广泛的应用，并且使用效果良好。本文在电缆用8076铝合金导体基础上，通过对合金成分设计、成形及热处理工艺的研究，拟开发出一种微合金化的8076铝合金导线。 为了进一步减小Fe元素对合金力学和导电性能的不利影响，研究了不同Mn元素加入量对合金组织与性能的影响；系统研究了拉拔工艺与合金线材组织和性能的关系，以期找出最佳的拉拔成形工艺；同时深入研究了热处理工艺对合金线材组织和性能的影响，，确定合理的热处理制度。Mn元素微合金化研究结果表明，Mn元素的加入，可以改变铸态和挤压态合金中Fe相的分布与形态，原来的针状、大片状、长条状Fe相断裂，变为间断的短棒状、粒状、球状等，减小对电导率和塑性的不利影响，大幅提高合金的抗拉强度；当Mn元素加入量为0.05%时，获得的线材综合性能较好。拉拔工艺研究表明，在拉拔过程中，中间道次加入退火工艺后，获得的线材导电性能普遍优于直接冷拔的，其中在Φ3.5mm处经过350℃中间退火后，最终拉拔线材综合性能最优，其电导率达到了61.32%IACS，抗拉强度为158.3MPa，伸长率为12.16%。退火工艺对线材性能影响研究表明，冷拔线材进行退火处理有利于改善其综合性能，解决电学和力学性能的矛盾；退火温度在160℃~400℃之间时，线材畸变的晶粒经回复再结晶形核成新的等轴晶粒，并随退火温度的提高再结晶晶粒逐渐增多并长大，电导率呈先上升后下降的趋势，当退火工艺为：退火温度330℃、保温时间1.5h、随炉冷却，线材综合性能最好，其电导率可达61.83%IACS，抗拉强度为108.6MPa，伸长率达21.86%，符合电缆导体用铝合金线的国家标准；此外，线材的电导率与退火后的冷却方式有关，其中随炉冷却得到的线材电导率要普遍高于空冷。时效热处理工艺对导线组织与性能影响研究表明，时效热处理使合金中析出了规则六方状的(Al,Mg)相和块状(Al,Mg,Si,Fe)相；固溶温度和时效工艺不同获得的导线性能也不同，双级时效较单级时效的电导率和伸长率有明显提高；当采用480℃/1h固溶+双级时效处理后，线材的综合性能达到最佳，电导率较冷拔态稍有提高，达到60.6%IACS，塑性大幅改善，伸长率达到了20.34%。
[Abstract]:With its high conductivity, high strength, high creep resistance and good economic value, 8000 series aluminum alloy conductor has been paid more and more attention, and has been widely used at home and abroad. On the basis of 8076 aluminum alloy conductor for cable, through the study of alloy composition design, forming and heat treatment process, a kind of 8076 aluminum alloy conductor with microalloying is developed. In order to further reduce the adverse effect of Fe on the mechanical and electrical properties of the alloy, the effects of different contents of Mn elements on the microstructure and properties of the alloy were studied, and the relationship between drawing process and the microstructure and properties of the alloy wire was systematically studied. At the same time, the effect of heat treatment on the microstructure and properties of alloy wire was studied, and the results of microalloying of element mn indicated that mn was added. The distribution and morphology of Fe phase in as-cast and extruded alloys can be changed. The original needle-shaped, large flake, long striped Fe phase breaks, and becomes discontinuous short rod, granular, spherical, etc., which reduces the adverse effect on conductivity and plasticity. The tensile strength of the alloy was greatly improved, and the comprehensive properties of the wire were better when the addition of Mn element was 0.05. The study of drawing process shows that the electrical conductivity of wire rod obtained by adding annealing process through intermediate pass is generally superior to that of direct cold drawing, and the comprehensive properties of wire drawn at 桅 3.5mm after intermediate annealing at 350 鈩

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