Al-Mg合金对2D石墨纤维网的润湿性及铺展速率分析

Wettability and spreading dynamics analysis of Al-Mg alloys on 2D-Gr fabrics

摘要:

本文使用静滴法研究了不同Mg含量(3.2, 4.5, 6.5, 8.5, 10, 13, 17 wt.% Mg)的Al-Mg合金在M40石墨纤维网上的润湿行为，重点讨论了Mg元素含量对润湿性及铺展速率的影响。 随着Al-Mg合金中的Mg含量从3.2 wt.%增加至17 wt.%，初始润湿角从115o降低到88.5o，而最终润湿角则由 96.7o降低到71o。由于M40石墨纤维的表面组织性质与普通石墨有较大的区别，因此与高密度碳平板相比，Al-Mg合金在石墨纤维网上的初始润湿角更小。而润湿角随Mg含量的增加而减小主要是源于Mg含量的增加可以显著降低Al-Mg合金的表面张力。基于Dezellus方程，进一步计算了Al-Mg合金在石墨纤维网上的铺展速率，计算结果与实验结果基本吻合。基于Miedema模型计算得到的铺展速率系数k也与实验结果基本吻合，此结果证明了Miedema模型在铺展速率计算方面应用的合理性。计算与实验结果均表明Mg元素含量的增加虽然可以显著降低润湿角，但对铺展速率影响不大。

Abstract:

In present work, the wetting behavior of Al-Mg alloys with different Mg amount (3.2, 4.5, 6.5, 8.5, 10, 13, 17 wt.% Mg) on M40 graphite fabrics was investigated by sessile drop method. The effect of Mg amount on the wettability and spreading behavior were discussed. The initial contact angle decreased from 115o in Al-3.2Mg/graphite fabrics to 88.5o in Al-17Mg/graphite fabrics system. The final contact angles decreased from 96.7o in Al-3.2Mg/graphite fabrics to 71o in Al-17Mg/graphite fabrics system. The initial contact angle measured on porous M40 graphite fabrics was lower than reported results on dense carbon plates due to the surface microstructure of M40 fibres. Due to surface tension decrease of Al-Mg alloys, the initial and final contact angles decreased with increasing of Mg amount. According to Dezellus equation, the kinetic constant (k) in spreading behavior was obtained from data fitting of experimental results. Miedema model was introduced in present work to calculate the theoretical k. The experimental or theoretical k changed little with increasing of Mg amount. Moreover, theoretical calculation values of k are very close to the experimental results, which indicate the applicability of Miedema model to the calculation of kinetic constant.