Interface cracking between functionally graded coatings and a substrate under antiplane shear
Interface cracking between functionally graded coatings and a substrate under antiplane shear
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DOI：
10.1016/s0020-7225(96)00055-9
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发表时间：
1996-12
影响因子：
6.6
通讯作者：
Z. Jin;R. Batra
中科院分区：
文献类型：
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作者：
Z. Jin;R. Batra
涂层技术在高温、腐蚀、氧化、磨损和界面等许多应用中发挥着重要作用。在本文中，我们研究了陶瓷和/或功能梯度涂层（FGM涂层）在反平面剪切作用下与基底之间的界面开裂。考虑了四种涂层模式，即单层均匀涂层、双层逐片均匀涂层、单层FGM涂层和双层FGM底涂层。计算了不同涂层模型的III型应力强度因子（SIFs）。在基底剪切模量为μL、涂层表面材料剪切模量为μL的情况下，单层FGM涂层对SIF的降低幅度较小，而上层均匀层和底层薄FGM涂层体系对SIF的降低幅度较大。当μL< μ0时，FGM涂层的SIF比均匀涂层的SIF大。然而，在这种情况下，FGM涂层可能仍然优于均匀涂层，因为FGM涂层通常在涂层和基体之间提供更好的结合强度。最后，讨论了SIF概念在FGM涂层断裂中的适用性。薄涂层中较大的模量梯度会严重限制SIFs的应用，因为SIFs主导区可能会落入裂纹尖端的非线性变形和损伤区。同样的论点也存在于一些界面裂缝解的界面模型中。
Coating technology plays a significant role in a number of applications such as high temperatures, corrosion, oxidation, wear, and interface. In this paper, we investigate the interface cracking between ceramic and/or functionally graded coatings (FGM coatings) and a substrate under antiplane shear. Four coating models are considered, namely single layered homogeneous coating, double layered piece-wise homogeneous coating, single layered FGM coating and double layered coating with an FGM bottom coat. Mode III stress intensity factors (SIFs) are calculated for the different coating models. In the case of μL> μ0where μ0is the shear modulus of the substrate and μLthe shear modulus of the material at the surface of the coating, it is found that the single layered FGM coating reduces SIF slightly, whereas the coating system with a top homogeneous layer and a thin FGM bottom layer reduces SIF significantly. In the case of μL< μ0the SIF is found to be larger for the FGM coatings than for the homogeneous coatings. The FGM coating, however, may still be superior to homogeneous coatings in this case as FGM coatings usually provide better bonding strength between the coating and substrate. Finally, the applicability of the SIF concept in the fracture of FGM coatings is discussed. Large modulus gradients in thin coatings may seriously restrict the application of SIFs as the SIF-dominant zone may fall into the crack tip nonlinear deformation and damage zone. The same argument exists for some interphase models in interface crack solutions.