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以热喷涂NiCrBSi涂层/钢基体为材料模型,利用将涂层置于受压侧的反向三点弯曲法试验,对热喷涂涂层界面断裂现象进行分析并建立相应的界面断裂韧性计算模型。结果表明,界面裂纹起始于三点弯曲试样中部,对应于加载压头与涂层接触区域正下方的界面上,并向两侧扩展,伴随涂层屈曲,形成分层屈曲的破坏形貌。根据分层屈曲形貌建立计算模型,通过分层屈曲几何参数与屈曲临界应力、涂层内真实应力以及界面断裂韧性的关系,获得界面断裂韧性值。
Using the thermal spraying NiCrBSi coating / steel substrate as the material model, the interface rupture phenomenon of the thermal spray coating was analyzed and the corresponding interfacial fracture toughness model was established by using the reverse three-point bending test with the coating on the pressure side. . The results show that the interface cracks begin at the middle of the three-point bending specimen, correspond to the interface just below the contact area between the loading head and the coating, and extend to both sides. With the buckling of the coating, the delaminated topography . According to the stratified buckling morphology, a computational model is established, and the interfacial fracture toughness value is obtained through the relationship between the stratified buckling geometric parameters and the critical stress of buckling, the real stress in the coating and the interfacial fracture toughness.