高性能Al-Mg-Si-Sc-Zr合金的热处理及变形工艺研究

发布时间：2018-03-08 07:31

本文选题：Al-Mg-Si-Sc-Zr合金　切入点：高低温时效　出处：《合肥工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：电力行业的不断发展使得高性能的全铝合金导线材料成为近年来的研究热点之一。本文采用真空铸造方法制备了含微量Sc、Zr的新型Al-Mg-Si-Sc-Zr合金,通过金相显微镜(OM)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)观察,硬度、导电率及拉伸性能测试等手段系统的研究了该合金在均匀化、固溶、时效热处理与轧制变形过程中的组织性能变化规律及微量Sc、Zr元素对合金的作用机理,确定了较为优化的热处理与变形工艺参数。真空铸造的新型Al-Mg-Si-Sc-Zr合金铸锭组织分布不均、晶粒尺寸较大,存在偏析现象。经520°C均匀化12h空冷处理后,合金晶界处的偏析得到明显改善,晶界光滑连续,非平衡相溶解,组织成分均匀。经520°C均匀化24h后,合金铸锭的导电率由52.1%IACS升高至55.5%IACS。挤压轧制后的Al-Mg-Si-Sc-Zr合金在600°C固溶处理过程中发生再结晶现象,固溶处理16h充分形成过饱和固溶体,晶粒未明显长大。新型Al-Mg-Si-Sc-Zr合金在350°C高温时效过程中,由于有大量起强化作用的A13(Sc,Zr)沉淀相粒子弥散析出,其硬度和导电率分别升高了34HV和6.7%IACS。在150°C低温时效过程中,由于有少量Mg2Si强化相的弥散析出,合金的硬度和导电率得到进一步的小幅提升。为了进一步改善新型Al-Mg-Si-Sc-Zr合金的力学性能,引入了冷轧变形处理工艺,增大组织中的位错密度。新型Al-Mg-Si-Sc-Zr合金(合金1)经600°C固溶+400°C高温时效+90%冷轧变形+150°C低温时效的形变热处理后,其抗拉强度、屈服强度、延伸率和导电率分别为325Mpa、231MPa、5.49%和55.0%IACS,综合性能良好。整个处理过程中主要利用了时效强化和形变强化等强化方式的相互作用,所得结果可以为工业化生产提供理论和技术支持。
[Abstract]:With the continuous development of power industry, high performance all-aluminum alloy conductor materials have become one of the research hotspots in recent years. In this paper, a new type of Al-Mg-Si-Sc-Zr alloy containing small amount of SCC Zr was prepared by vacuum casting. The homogenization and solution of the alloy were studied by means of metallographic microscope, scanning electron microscope (SEM) and transmission electron microscope (TEM). The hardness, conductivity and tensile properties of the alloy were tested systematically. The changes of microstructure and properties during aging heat treatment and rolling deformation and the action mechanism of trace amount of Scnr on the alloy were determined. The optimum technological parameters of heat treatment and deformation were determined. The microstructure of the new Al-Mg-Si-Sc-Zr alloy cast by vacuum casting was unevenly distributed. After being homogenized at 520 掳C for 12 h, the segregation at the grain boundary was obviously improved, the grain boundary was smooth and continuous, the non-equilibrium phase dissolved, and the microstructure was homogeneous after being homogenized at 520 掳C for 24 hours. The electrical conductivity of alloy ingot increased from 52.1 to 55.5 IACs. The recrystallization of Al-Mg-Si-Sc-Zr alloy after extrusion rolling occurred during the treatment of 600 掳C solution, and the supersaturated solid solution was formed after 16 hours of solution treatment. The hardness and conductivity of the new Al-Mg-Si-Sc-Zr alloy were increased by 34HV and 6.7IACSs respectively due to the dispersion precipitation of a large number of A13SSC-ZrZr precipitated particles during high temperature aging at 350 掳C, the hardness and conductivity of the new Al-Mg-Si-Sc-Zr alloy increased by 34HV and 6.7IACSrespectively during the aging process at 150 掳C at low temperature, the hardness and conductivity of the alloy were increased by 34HV and 6.7HV, respectively. In order to improve the mechanical properties of the new Mg2Si alloy, the cold rolling process was introduced in order to further improve the mechanical properties of the alloy, due to the dispersion precipitation of a small amount of Mg2Si strengthened phase, the hardness and conductivity of the alloy were further improved. The tensile strength and yield strength of a new type of Al-Mg-Si-Sc-Zr alloy (alloy 1) treated with 90% 掳C cold rolling and deforming 150 掳C at low temperature aging at 600 掳C were increased, and the tensile strength and yield strength of the new type of Al-Mg-Si-Sc-Zr alloy (alloy 1) were increased, and the tensile strength and yield strength of the new alloy (alloy 1) were obtained. The elongation and conductivity are 325 Mpaan 231MPaI 5.49% and 55.0% IACS.The interaction of aging strengthening and deformation strengthening is mainly used in the whole process. The results can provide theoretical and technical support for industrial production.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG166.3

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