Abstract The effect of carbon addition and cooling rate on the lamellar structure of peritectic Ti-46.5Al–5Nb-0.2B-0.2C (at.%) alloy was studied. The studied alloys with a carbon content of 0.2, 0.5, 0.7 and 1.0 at.% were prepared by vacuum induction melting in graphite crucibles. The as-cast samples were subjected to solution annealing in a single α (Ti-based solid solution) phase field followed by cooling at four constant rates ranging from 5 to 50 °C/min. The increase in carbon content leads to an increase in both start and finish α phase decomposition temperatures. During continuous cooling, the carbon atoms segregate along α2(Ti3Al)/γ(TiAl) lamellar interfaces and hinder lateral growth of γ lamellae. The interlamellar spacing decreases with increasing carbon content and increasing cooling rate. A relationship describing the complex influence of carbon content and cooling rate on α2-α2 interlamellar spacing λ is proposed. Vickers microhardness HVm increases with increasing both the carbon content and cooling rate. The Vickers microhardness depends on interlamellar spacing λ according to the Hall-Petch relationship.

中文翻译：

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加碳和冷却速度对包晶TiAl基合金层状组织的影响

摘要 研究了碳添加量和冷却速度对包晶Ti-46.5Al-5Nb-0.2B-0.2C (at.%)合金层状结构的影响。通过在石墨坩埚中真空感应熔炼制备碳含量为 0.2、0.5、0.7 和 1.0 at.% 的研究合金。铸态样品在单个α（Ti 基固溶体）相场中进行固溶退火，然后以 5 至 50 °C/min 的四个恒定速率冷却。碳含量的增加导致开始和结束 α 相分解温度的增加。在连续冷却过程中，碳原子沿α2(Ti3Al)/γ(TiAl)层状界面偏析，阻碍了γ层状的横向生长。层间距随着碳含量的增加和冷却速度的增加而减小。提出了描述碳含量和冷却速率对 α2-α2 层间距 λ 的复杂影响的关系。维氏显微硬度 HVm 随着碳含量和冷却速度的增加而增加。根据霍尔-佩奇关系，维氏显微硬度取决于层间间距 λ。