激光熔覆对改善等离子涂层界面结合性能的研究

研究激光熔覆对改善等离子涂层界面的作用，基体待喷表面采用激光熔覆工艺预处理，在涂层－基体的界面处形成成分、显微硬度呈梯度分布的熔覆层，三点弯曲试验结果表明：界面梯度有显改善喷涂材料的界面结合状况，使界面承受外载茶的能力提高，并用相关的有限元程序分析了试样承载时界面处剪切应力的分布。

IMPROVEMENT OF COHESION PROPERTIES OF INTERMCE IN PLASMA SPRMING COATING BY LASER CLADDING

The present study is focused on the improvement of cohesion properties of interface betweenplasma-sprayed coatings and substrate by a laser cladding technique(LCT). Within the laser-clad layer,there exists a gradient distribution in chemical composition and mechanical performance, which has beenconfirmed by SEM observation and micro-hardness measurement. The residual stress due to mismatches inthermal and mechanical properties between coatings and substrate can be markedly reduced and smoothedout. To examine the microstructure changes and crack propagation in the coating and interface duringloading, an experimental test has also been conducted on three-point bending samples in an SEM with aloading equipment installed. The experimental results have shown clearly that the interface cohesion canbe improved with LCT pretreatment, and the capability of the interface to withstand the shear stress aswell as to resist micro-cracking has been enhanced, and analysis on distribution of shear stress at interfaceunder loading has been conducted using ANSYS FEM code.