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比较研究了H420低合金高强钢板热浸镀55%Al-Zn-1.6%Si(≤0.1%Ti)和55%Al-Zn-1.6%Si金属间反应层组织及生长动力学.利用光学显微镜、SEM、EDS和XRD对反应层微观组织、厚度、元素分布及相组成进行了分析.结果表明,金属间反应层都主要由Fe2Al5,Fe4Al13和Fe-Al-Si金属间化合物三相构成.Fe2Al5相与Fe4Al13相交界区域存在少量的Fe-Al-Si-Mn固溶体析出物,可能主要因基板中的Mn元素扩散进入合金层.金属间反应层的生长速率遵循抛物线规律.相比较,H420+GL+Ti金属间反应层总厚度平均降低了3.25μm,Fe2Al5相厚度平均降低了1.83μm.主要原因是,Ti-Al键能明显要大于Fe-Al键能,添加Ti影响了Fe-Al的相互作用,从而抑制Fe-Al金属间化合物的形成和生长,最终降低了反应层厚度.
The microstructure and growth kinetics of 55% Al-Zn-1.6% Si (≤0.1% Ti) and 55% Al-Zn-1.6% Si hot-dip coating on H420 low-alloy high strength steel were studied comparatively.Using optical microscope, The microstructure, thickness, elemental distribution and phase composition of the reaction layer were analyzed by SEM, EDS and XRD.The results showed that the intermetallic layer mainly consisted of three phases of Fe2Al5, Fe4Al13 and Fe-Al-Si intermetallic compounds, The Fe-Al-Si-Mn solid solution precipitates in the interface with Fe4Al13 may be mainly due to the diffusion of Mn in the substrate into the alloy layer.The growth rate of the intermetallic layer obeys the parabolic law.Compared with H420 + GL + The average thickness of Ti intermetallic layer decreased by 3.25μm and the thickness of Fe2Al5 phase decreased by 1.83μm on average.The main reason was that the Ti-Al bond was obviously larger than the Fe-Al bond energy and the addition of Ti affected the interaction of Fe-Al , Thereby inhibiting the formation and growth of Fe-Al intermetallic compounds, eventually reducing the thickness of the reaction layer.