Nb离子注入γ-TiAl的高温循环氧化行为

Cycling Oxidation Behavior of Nb-ion Implanted γ-TiAl

研究了Nb离子注入的γ TiAl合金在 1 1 2 3K和 1 1 73K空气中的高温循环氧化行为 ,用配有能谱仪的扫描电子显微镜对氧化层的形貌、显微结构进行了分析 ,用俄歇谱仪分析了注入元素和氧化层中各元素的分布 .结果表明 :Nb离子注入可以提高γ TiAl合金的抗循环氧化性能 .提高其抗氧化性能的主要原因归结于Nb离子在TiO2 中的掺杂作用 .高价Nb的掺杂 ,降低了TiO2 的缺陷浓度 ,使TiO2 的生长受到抑制 ,在氧化初期形成了Al2 O3 保护层 ,从而推迟了氧化层的剥落时间 .但Nb离子注入的γ

The thermal cycling oxidation behaviors of Nb ion implanted γ TiAl in air were studied in the temperature range of 1?123?～1?173?K. The microstructures of the oxide scales were examined by SEM equipped with EDS. Nb distribution and depth profiles of elements were analyzed by AES. The results indicated that the cyclic oxidation resistance of γ TiAl alloy could be improved by Nb ion implantation. The reason why Nb ion implantation improves the cyclic oxidation properties may be ascribed to doping of the titania lattice by Nb 5+ ions, which may inhibit the growth of TiO 2 and enhance the growth rate of Al 2O 3. The formation of Al 2O 3 protective layer at the early stage decreased the oxidation rate and delayed the spallation of oxide scale. But Nb ion implanted γ TiAl has no long effect to thermal cycling oxidation resistance.