Oxidation behavior of protective Ti-Al-Cr based coatings applied on the γ-TiAl alloys Ti-48-2-2 and TNM-B1
Oxidation behavior of protective Ti-Al-Cr based coatings applied on the γ-TiAl alloys Ti-48-2-2 and TNM-B1
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DOI：
10.1016/j.surfcoat.2018.05.067
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发表时间：
2018-09-15
影响因子：
5.4
通讯作者：
Knittel, Stephane
中科院分区：
文献类型：
--
作者：
Laska, Nadine;Braun, Reinhold;Knittel, Stephane
采用磁控溅射技术在TiAl合金Ti-48-2-2和TiM-B1上制备了添加少量Y或Zr的Ti-Al-Cr基金属间化合物涂层。在实验室空气中的循环热暴露条件下，研究了涂层衬底在850℃至950℃的温度范围内的氧化行为。在所研究的温度范围内，Ti-Al-Cr-Y涂层对两种TiAl合金均具有良好的抗氧化性能，循环次数可达1000 h。在Ti-48-2-2衬底上制备的Ti-Al-Cr-Zr涂层也得到了类似的结果。当在900℃和950℃下进行热循环时，沉积在TNM-B1合金上的后者保护层局部退化，可能是由于涂层中的裂纹导致衬底氧化造成的。在高温暴露过程中，由于Al和Cr的贫化，涂层的微观结构发生了变化。与TnM-B1合金相比，Ti-48-2-2合金的铬含量为2at.%，铝含量较高，从而减少了涂层与含铬基材之间的互扩散，抑制了氧化保护层中的相变。
Intermetallic Ti-Al-Cr based coatings with small additions of yttrium or zirconium were deposited on the gamma-TiAl alloys Ti-48-2-2 and TNM-B1 using magnetron sputtering. The oxidation behavior of the coated substrates was investigated in the temperature range between 850 degrees C and 950 degrees C under cyclic thermal exposure conditions in laboratory air. Excellent oxidation protection to both TiAl alloys was provided by the Ti-Al-Cr-Y coating in the studied temperature range for up to 1000 1 h-cycles. Similar results were obtained for the Ti-Al-Cr-Zr coating on the Ti-48-2-2 substrate. When thermally cycled at 900 degrees C and 950 degrees C, the latter protective layer deposited on the TNM-B1 alloy locally degraded probably caused by cracks in the coating leading to substrate oxidation. During high temperature exposure the microstructure of the coatings changed due to depletion in Al and Cr. Because alloy Ti-48-2-2 contains 2 at.% Cr and has a higher Al content compared to the TNM-B1 alloy, interdiffusion between coating and the Cr bearing substrate is reduced, retarding phase transformation in the oxidation protective layers.