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利用非自耗真空电弧熔炼炉获得了Ti-45Al-xFe合金钮扣锭,并利用光学显微镜(OM)、扫描电镜(SEM)和洛氏硬度仪研究了Fe含量的变化对Ti-45Al-xFe合金铸态组织及硬度的影响规律。结果表明:随着Fe含量的增加,Ti-45Al-xFe合金的显微组织演化过程依次经历了如下阶段:具有四重对称的树枝晶→具有四重对称的树枝晶+枝晶间较小的γ相+少量的B2相→具有六重对称的树枝晶+板条状的γ相+大量的B2相,而且在Ti-45Al-xFe合金中B2相的析出量也随之增加。另外,随着Fe含量的增加,Ti-45Al-xFe合金中的凝固初生相由β相向α相演化。通过对Ti-45Al-xFe合金进行硬度试验发现,其硬度拟合曲线呈现先降低后增加的变化趋势。这主要是由于Ti-45Al-xFe合金中B2相的大量析出及其显微组织形态的变化所致,当Fe含量大于5%(原子分数)时,Ti-45Al-xFe合金的显微组织中的B2相的形态发生了明显的变化,并且该B2相的内部呈现蜂窝形状。因此,由于该B2相的组织形态导致了Ti-45Al-xFe合金的硬度值增加。
Ti-45Al-xFe alloy ingot ingot was obtained by non-consumable vacuum arc melting furnace. The effects of the change of Fe content on the microstructure of Ti-45Al-xFe alloy were studied by optical microscope (OM), scanning electron microscope (SEM) and Rockwell hardness tester Influence of Casting Microstructure and Hardness of Alloy. The results show that the microstructure evolution of Ti-45Al-xFe alloy goes through the following phases in sequence with the increase of Fe content: dendrites with quadruple symmetry → quaternary symmetry with smaller dendrite + dendrite γ phase + a small amount of B2 phase → six symmetrical dendrites + lath γ phase + a large number of B2 phase, and the precipitation of B2 phase in Ti-45Al-xFe alloy also increases. In addition, as the Fe content increases, the solidified primary phase in Ti-45Al-xFe alloy evolves from β phase to α phase. According to the hardness test of Ti-45Al-xFe alloy, the curve of hardness fitting showed the trend of decreasing firstly and then increasing. This is mainly due to the massive precipitation of B2 phase in Ti-45Al-xFe alloy and the change of its microstructure. When the content of Fe is more than 5% (atomic fraction), the microstructure of Ti-45Al-xFe alloy Of the B2 phase morphology has undergone significant changes, and the inside of the B2 phase honeycomb shape. Therefore, the hardness value of the Ti-45Al-xFe alloy is increased due to the morphology of the B2 phase.