Al_2O_3/3wt%TiO_2爆炸喷涂层的纳米压痕力学特性

Nanoindentation Mechanical Properties of Al_2O_3/3wt%TiO_2 Detonation Sprayed Coatings

研究了Al2O3 /3wt%TiO2 爆炸喷涂层的微观结构特征和纳米压痕力学特性。涂层的纳米压痕力学性能具有明显的各向异性行为和离散性。涂层表面比断面具有更为优良的抵抗外加负载和卸载后良好的弹性恢复的能力。表面和断面平均硬度分别为 10 3GPa和 2 9GPa,而表面和断面平均弹性模量分别为 170 7GPa和 234 5GPa。涂层各向异性的力学性能是由于爆炸喷涂的投影本质导致涂层断面的片层结构和平行于基体界面的裂纹形成。涂层断面比表面存在着尺度分布较宽的孔洞、裂纹等缺陷。

Both the microstructures of the detonation sprayed Al2O3/3wt% TiO2 coating and the indentation load-displacement behavior of the coating tested with a Berkovich indenter were investigated. The coatings exhibited apparently anisotropic nanoindentation mechanical behaviors and dispersibility. Compared to the cross-section, the surface of the coatings had better ability to resist applied load and better elastic recovery after unloading. The mean hardness of the surface and cross-section of the coating were 10.3 GPa and 2.9 GPa, respectively. While mean Young's modulus of the surface and cross-section of the coating were 170.7 GPa and 234.5 GPa, respectively. The anisotropic nanoindentation mechanical properties were mainly due to anisotropic microstructures of the detonation sprayed coating. Other than the surface, the cross-section structure corresponded to splat interface and many cracks parallel to the substrate. The cross-section had more pores; bigger pore size and a more unhomogeneneous distribution than the surface.