H. Zhou, F. Li, B. He, J. Wang, B. D. Sun, Shanghai Jiao Tong University, Shanghai, China
High temperature titanium alloys are considered as good candidate materials for many aerospace applications. In order to increase the titanium alloy use temperatures and oxidation resistance, plasma spraying thermal barrier coatings on the titanium alloys is considered as an effective method. The effect of plasma spraying process on microstructure and microhardness of the titanium alloy was investigated by SEM, EDAX and microhardness test. The results show that the microstructure of the titanium alloy inside the substrate keeps unchanged after plasma spraying, no interaction and atomic diffusion happen evidently at the bond coat/substrate interface. However there exists a thin plastic deformed zone in the substrate beneath the bond coat/substrate interface after plasma spraying. The residual stresses are induced inside the titanium alloy due to the thermal expansion mismatch and the temperature gradient inside the substrate during spraying process which lead to generating microcracks beneath the bond coat/substrate interface and the increase of microhardness in the substrate.Keywords Titanium alloy, Plasma spraying, Microstructure, MicrohardnessI would like the paper to be considered for publication in a special issue of the Journal of Thermal Spray Technology
Summary: Thermal barrier coatings have been air plasma sprayed on a titanium alloy. The effect of plasma spraying process on the microstructure and microhardness of the titanium alloy is investigated using SEM, EDAX and microhardness test in the work.
