Mechanical properties of composite coating on cast iron by laser

ABSTRACT

We report a composite coating on vermicular graphite cast iron reinforced with Al₂O₃ particulates, processed by selective laser surface alloying, with the thickness of ∼600 µm and coverage fraction of 20%. The original microstructure was thus considerably modified. Different fractions of the Al₂O₃ particulates were added, ranging from 5 to 25 wt-%. Microhardness and strength were both increased, due to the formation of the composite coating, which led to a series of strengthening mechanisms. In addition, in thermal fatigue test, the crack density was reduced, due to the surface composite coating and the particular scanning strategy. Cracking on the sample surface was effectively restrained by the composite coating.

KEYWORDS:

• Electron microscopy
• Mechanical characterization
• Grain refinement
• Hardness measurement

Acknowledgements

This work is supported by Project 985-Bionic Engineering Science and Technology Innovation of Jilin University, the Pearl River S&T Nova Program of Guangzhou (No. 2014J2200095) and the Key Project of Science and Technology of Jilin Province (Grant No. 20150204058GX).