NDLI: Microstructure Characteristics and High-Temperature Oxidation Behavior of Plasma-Sprayed and Laser-Remelted MCrAlY Coatings on TiAl Intermetallics

Content Provider	The American Society of Mechanical Engineers (ASME) Digital Collection
Author	Tian, Zongjun Shen, Lida Liu, Zhidong Huang, Yinhui
Copyright Year	2011
Abstract	In order to further improve the high-temperature oxidation resistance of TiAl intermetallic alloys, MCrAlY coatings were fabricated by plasma spraying and plasma spraying-laser remelting technologies. The microstructures of the as-sprayed and laser-remelted MCrAlY coatings were studied. In addition, the oxidation behaviors at 850 °C for three samples were investigated. One sample is the matrix of TiA1 intermetallic alloys, the other one is processed by plasma-spraying MCrAlY coatings, and the third one is processed by plasma-spraying and laser-remelting MCrAlY coatings. It was revealed that the oxidation resistance of TiAl intermetallics is weak due to lack of protection of Al2O3 film formed on the surface. The plasma-sprayed MCrAlY coatings have better oxidation resistance than the TiAl intermetallics although the plasma-sprayed MCrAlY coatings have high density of porosity and a typical layered structure. It is demonstrated that most of the holes can be eliminated by laser remelting, leading to the best oxidation resistance of the third sample with the laser-remelted coatings. The high oxidation resistance of the laser-remelted coatings is mainly attributed to three aspects: firstly, an Al enriched zone on the coating surface is formed during laser remelting, which is transformed into a protective Al2O3 film during oxidation process. Secondly, laser remelting eliminates most of the defects in plasma-sprayed coatings and enhances its density, thus decreases the channel of oxidation diffusion in high temperature oxidation process. Thirdly, rapid cooling of laser remelting results in a grain refinement and a preferred oxidation of Al at the initial stage, leading to a reduction of oxidation rate.
Sponsorship	Manufacturing Engineering Division
Starting Page	381
Ending Page	390
Page Count	10
File Format	PDF
ISBN	9780791844304
DOI	10.1115/MSEC2011-50145
Volume Number	ASME 2011 International Manufacturing Science and Engineering Conference, Volume 1
Conference Proceedings	ASME 2011 International Manufacturing Science and Engineering Conference
Language	English
Publisher Date	2011-06-13
Publisher Place	Corvallis, Oregon, USA
Access Restriction	Subscribed
Subject Keyword	Mcraly coatings High-temperature oxidation resistance Tial intermetallics Plasma spraying Microstructure Laser remelting Lasers Titanium aluminide Oxidation High temperature Coatings Plasmas (ionized gases)
Content Type	Text
Resource Type	Article

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