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用热重分析 (TGA)法研究了 Ti- 5 0± 2 Al(at% )在各种条件下 10 0 h内的高温氧化行为。结果显示 :Ti Al基合金在总体上随 Al含量的增大、其氧化增重 (Δ M)有减小的趋势 ,但中间成分 Ti- 5 0 Al合金的 ΔM在不同条件下 (尤其是氧化环境较为苛刻时 )会有所波动。Ti- 48Al的抗氧化性不如 Ti- 5 2 Al的原因在于后者氧化表层中 Al2 O3含量增加 ,而 Al2 O3中离子扩散系数小 ,阻碍了反应离子的互扩散 ,从而减缓了反应速度。 Ti Al的氧化动力学规律对 Al波动不甚敏感 ,但对氧化条件敏感。表面氧化物基本组成为 (Ti O2 +Al2 O3)。
The thermogravimetric analysis (TGA) method was used to investigate the high temperature oxidation behavior of Ti-5 0 ± 2 Al (at%) under various conditions for 10 h. The results show that the ΔM of TiAl-based alloy tends to decrease with the increase of Al content. However, the ΔM of the intermediate alloy Ti-5 0 Al alloy decreases with the increase of Al content under different conditions The environment is more harsh) will fluctuate. The reason why the oxidation resistance of Ti-48Al is inferior to that of Ti-5 2 Al is that the content of Al 2 O 3 in the latter oxide layer increases while the ion diffusion coefficient in Al 2 O 3 is small, which hinders the mutual diffusion of the reaction ions and slows down the reaction rate. The oxidation kinetics of TiAl is not sensitive to Al fluctuations but sensitive to oxidation conditions. The surface oxide basic composition (Ti O2 + Al2 O3).