Abstract No.:	4818
Title:	Inter-splat lamellar pores resulting from delamination due to weak interface adhesion
Authors:	Guang-Rong Li / Xi'an Jiaotong University, P.R. China Lin Chen* / State Key Laboratory for Mechanical Behavior of Materials, Xian Jiaotong University, China Shu-Wei Yao/ State Key Laboratory for Mechanical Behavior of Materials, Xian Jiaotong University, China Guan-Jun Yang/ State Key Laboratory for Mechanical Behavior of Materials, Xian Jiaotong University, China Cheng-Xin Li/ State Key Laboratory for Mechanical Behavior of Materials, Xian Jiaotong University, China Chang-Jiu Li/ State Key Laboratory for Mechanical Behavior of Materials, Xian Jiaotong University, China
Abstract:	The nonbonded lamellar interface in thermally-sprayed coatings has been never bonded, and the effective bonding is preferably formed at splat center than periphery due to higher impact pressure. However, all segments, resulting from splat dividing by intra-splat cracks, at both splat center and periphery have both bonded and nonbonded interfaces. This fundmental contradiction has not been understood up to now. In this study, to comprehensively understand the nonbonded splat/splat interface formation mechanism, both adjacent surfaces of an inter-splat interface were examined in comparison to the free surface of splat. Results show that free splat surface was relatively smooth. However, both adjacent surfaces of an inter-splat interface were relatively rough. In addition, the residual stresses in single splats were measured by Raman spectroscopy with comparison to theoretical value. The energy released by dislocation and cracks was also calculated. The results demonstrate that nonbonded splat/splat interfaces have ever bonded and the nonbonding feature could be attributed to the fracture of the bonded interface due to the interface shear stress resulting from the splat shrinking during cooling process. Consequently, the nonbonded lamellar interface could be regarded as ever bonded rather than never bonded, especially for those interface regions with rough surface morphology.

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