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研究了TiAl金属间化合物及表面涂层在空气中的高温循环氧化行为。结果表明:在800℃时TiAl合金具有较好的抗高温氧化行为,但当温度高于800℃时,TiAl合金表面未能形成单一的Al2O3保护层,而是形成外3层为疏松的TiO2层,内层为TiO2+Al2O3的混合氧化物层,因而使得TiAl合金的抗高温循环氧化性能严重蜕化。TiAl合金经过Cr改性铝化处理后,表面形成了具有立方Ll2结构的Al67Ti26Cr7层,立方Ll2结构的Al67Ti26Cr7不仅具有较高的铝含量,而且具有优良的韧性,因而使得处理后的TiAl合金具有良好的抗高温循环氧化性能。铝化物涂层尽管有很高的铝含量,但由于铝化得到的TiAl3相具有四方形结构,涂层非常脆,故该涂层抗高温循环氧化性能有待进一步提高
The cyclic oxidation behavior of TiAl intermetallics and surface coatings in air at high temperature was studied. The results show that the TiAl alloy has better high temperature oxidation resistance at 800 ℃. However, when the temperature is higher than 800 ℃, a single Al2O3 protective layer can not be formed on the surface of TiAl alloy, , The inner layer is a mixed oxide layer of TiO2 + Al2O3, thereby making the TiAl alloy severely degeneration under high temperature cyclic oxidation performance. TiAl alloy after Cr modified aluminization, the surface has a cubic Ll2 structure Al67Ti26Cr7 layer, cubic Ll2 structure Al67Ti26Cr7 not only has a high aluminum content, but also has excellent toughness, which makes the treated TiAl alloy has good The high temperature cycle oxidation performance. Although the aluminide coating has a high aluminum content, the TiAl3 phase obtained by aluminizing has a tetragonal structure and the coating is very brittle, so the performance of the coating at high temperature for cyclic oxidation needs to be further improved