A series of 2IML multilayer coatings (composed of two hard intermetallic (IML) layers and two soft sublayers) with the different thickness of the first IML sublayer have been built to develop our mechanistic understanding of what controls its fatigue performance. Experimental investigations of these multilayer coatings reveal that decreasing the IML-Top layer’s thickness provides improved fatigue resistance. This improvement could be linked to: (1) the increased difficulty of surface crack initiation due to the limitation of the strain ranges experienced at the top surface and (2) the shorter crack propagation period in a thinner IML-Top layer.

中文翻译：

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软多层涂层内金属间亚层厚度变化对整体疲劳性能的影响

已经建立了具有不同的第一IML子层厚度的一系列2IML多层涂层（由两个硬金属间（IML）层和两个软子层组成），以发展我们对控制其疲劳性能的机制的理解。对这些多层涂层的实验研究表明，降低IML-Top层的厚度可提高抗疲劳性。这种改善可能与以下方面有关：（1）由于顶表面承受的应变范围的限制而增加了表面裂纹萌生的难度，（2）在较薄的IML-Top层中，裂纹扩展时间更短。