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为了改善钢铁材料的耐高温腐蚀性能,用光束合金化方法在45钢表面合成了Fe-Al金属间化合物涂层。采用扫描电子显微镜、能量弥散X射线分析和X射线衍射研究了光束合金化工艺参数(粉末预置量m和热输入量q)对合金化层的化学成分、显微组织及其物相组成的影响。实验结果表明:减小比能量(E=q/m)将导致合金化层的熔宽和熔深减小,从而使合金化层含Fe量减少,含Al量增加;该实验条件下,获得了Fe/Al原子数比为2.4～19.2的合金化层。由比能量决定的Fe/Al原子数比是合金化层显微组织及其物相组成的重要影响因素,合金化层的显微组织有3种类型:α-Fe固溶体、α-Fe固溶体+Fe3Al金属间化合物及FeAl+AlFe3C0.5金属间化合物。降低热输入或增加粉末预置量均可引起合金化层中Fe/Al原子数比的降低,有助于Fe-Al系(Fe3Al或FeAl)金属间化合物的合成。
In order to improve the high temperature corrosion resistance of steel, the Fe-Al intermetallic compound coating was synthesized on the surface of 45 steel by the beam alloying method. The chemical composition, microstructure and phase composition of the alloying layer were investigated by scanning electron microscopy, energy dispersive X-ray diffraction and X-ray diffraction. The effects of the beam alloying parameters (powder pre-m and heat input q) influences. The experimental results show that the reduction of the specific energy (E = q / m) will lead to the decrease of the melting width and the penetration depth of the alloying layer, so that the content of Fe and the content of Al in the alloyed layer decrease. Under this experimental condition, The alloying layer has a Fe / Al atomic ratio of 2.4 to 19.2. The specific energy of the Fe / Al atomic ratio is the alloying layer microstructure and its phase composition of the important factors, the alloying layer microstructure has three types: α-Fe solid solution, α-Fe solid solution + Fe3Al Intermetallic compounds and FeAl + AlFe3C0.5 intermetallic compounds. Lowering the heat input or increasing the amount of powder pretreatment can cause the decrease of the Fe / Al atomic ratio in the alloying layer and contribute to the synthesis of the Fe-Al-based (Fe3Al or FeAl) intermetallic compound.