Al-5Ti-0.2C细化剂对7085铝合金形核及过冷度的影响

发布时间：2018-05-27 23:34

本文选题：铝合金 + Al-Ti-.C细化剂　；参考：《中南大学学报(自然科学版)》2015年08期

【摘要】：在7085铝合金凝固过程中添加不同质量分数的Al-5Ti-0.2C细化剂,对比其铸锭凝固组织,并用DSC测定其凝固过程熔体过冷度,探讨Al-5Ti-0.2C细化剂对铝熔体形核与过冷度的影响。研究结果表明:Al-5Ti-0.2C细化剂能够明显细化晶粒,当细化剂质量分数为0.5%时细化效果最好;细化剂质量分数的差异对DSC曲线中的熔化曲线影响较小,而凝固曲线有明显差异;在凝固过程中增大细化剂质量分数,铝熔体形核过冷度与最大过冷度都呈递减趋势,当细化剂质量分数超过0.5%时,过冷度不再有明显递减趋势;Ti C颗粒是铝熔体异质形核的核心,凝固过程中Ti C颗粒的发生团聚,从而增大形核基底颗粒粒度,减小润湿角与临界形核能,最终减小熔体中形核所需过冷度。
[Abstract]:Al-5Ti-0.2C refiner with different mass fraction was added to 7085 aluminum alloy during solidification. The solidification microstructure of ingot was compared. The melt undercooling degree during solidification was measured by DSC, and the effect of Al-5Ti-0.2C refiner on the nucleation and undercooling of aluminum melt was discussed. The results show that the grain size can be significantly refined by the:% Al-5Ti-0.2C refiner, and the effect of refining is the best when the mass fraction of the refiner is 0.5, the difference of the mass fraction of the refiner has little effect on the melting curve of DSC curve, but the solidification curve has obvious difference. In the process of solidification, when the mass fraction of the refiner is increased, the nucleation undercooling degree and the maximum undercooling degree of aluminum melt show a decreasing trend. When the mass fraction of the refiner exceeds 0.5, There is no longer a decreasing trend of undercooling. Tic particles are the core of heterogeneous nucleation of aluminum melt. During solidification, tic particles are agglomerated, thus increasing the particle size of nucleation substrate, reducing wetting angle and critical nuclear energy. Finally, the degree of undercooling required for nucleation in the melt is reduced.
【作者单位】：中南大学机电工程学院高性能复杂制造国家重点实验室;
【基金】：国家重点基础研究发展规划(973计划)项目(2010CB731706,2012CB619504)~~
【分类号】：TG292

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