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研究了均匀化和铸态TiAl合金在(Na,K)2SO4混合熔盐中的热腐蚀行为,讨论了α2相在均匀化和铸态TiAl合金热腐蚀中的作用机理。结果表明:含少量α2相的均匀化TiAl合金呈现良好的抗热腐蚀行为,腐蚀产物中的富Al2O3相成层状分布,在腐蚀产物/基体界面形成连续的富Ti硫化物;而含有大量层状组织的铸态TiAl合金则遭受严重的热腐蚀,在腐蚀初期,α2+γ构成的层状组织优先腐蚀,铸态TiAl合金的腐蚀层主要由富Ti的氧化物和硫化物组成,形成的混合膜黏附性差,较易剥落。
The hot corrosion behavior of homogenized and as-cast TiAl alloy in (Na, K) 2SO4 mixed molten salt was studied. The mechanism of α2 phase homogenization and hot corrosion in as-cast TiAl alloy was discussed. The results show that the homogenized TiAl alloy containing a small amount of α2 phase exhibits good anti-hot corrosion behavior. The Al2O3-rich phase in the corrosion product is layered and forms continuous Ti-rich sulfides at the corrosion product / matrix interface. The as-cast TiAl alloy suffered serious hot corrosion. At the initial stage of corrosion, the layered structure of α2 + γ preferentially corroded. The corrosion layer of the as-cast TiAl alloy mainly consisted of Ti-rich oxides and sulfides. Mixed membrane adhesion is poor, easier to peel off.