P. H. Liao, C. Zhang, C. Coddet, University of Technology Belfort-Montbeliard, Belfort Cedex, France; W. Y. Li, Northwestern Polytechnical University,, Xi'an, China; X. GUO, UTBM, Belfort, France
Al-Si alloys are widely used in the automotive industry and other applications owing to its light weight feature. The Al-Si coatings are commonly used for salvage and build-up of parts made of aluminium, magnesium and their alloys. They have also been used as abradable coatings for gas turbine engines. The converntional thermal spray processes, such plasma spraying, were used to fabricated these coatings. The emerging cold spraying process is also an effective alternative to produce the high quality Al-Si coatings. However, there are few reports focusing on this interesting applications. In this paper, the deposition features of Al-12Si alloy coatings by cold spraying with relatively large powder particles were investigated. More attention has been paid on the microstructure evolution of the coatings deposited under different spray conditions. It was found that a very dense Al-12Si coating can be deposited under certain condition with the particles experiencing extensive deformation and flattening. The impact fusion was clearly observed at the interfaces of the deposited particles in the coating, which promotes the formation of metallurgical bonding between particles and thus enhances the bonding of coatings. On the other hand, the spherical Si enriched precipitates were formed in α-Al matrix owing to the thermal effect during deposition, which could be attributed to the relatively high coating microhardness.
Summary: In this paper, the deposition features of Al-12Si alloy coatings by cold spraying with relatively large powder particles were investigated. More attention has been paid on the microstructure evolution of the coatings deposited under different spray conditions.
