Microstructure and performance of cold sprayed Al-SiC composite coatings with high fraction of particulates

• Published in: Surface & coatings technology 2017-05, Vol.318, p.62-71
• Main Authors: Kumar, S., Reddy, Sai Kiran, Joshi, S.V.
• Format: Article
• Language: English
• Subjects: Al-SiC; Aluminum; Cold spray; Cold spraying; Correlation analysis; Deposition; Frictional wear; Heat treatment; Manufacturing and materials engineering; Mechanical properties; Metal matrix composites; Microstructure; Particulate composites; Particulates; Porosity; Production Technology; Produktions- och materialteknik; Produktionsteknik; Sliding friction; Sprayed coatings; Studies; Substrates; Thermal degradation; Wear; Wettability
• ISSN: 0257-8972; 1879-3347; 1879-3347
• DOI: 10.1016/j.surfcoat.2016.11.047

Deposition of metal matrix composites (MMCs) through thermal spraying has traditionally presented problems associated with heterogeneity, porosity, and low wettability of particulates with matrix. Cold spray is a very rapid deposition process which is suitable for depositing a variety of ductile materials without any thermal degradation. Many researchers have attempted to deposit Al-SiC MMCs with 10–20% SiC using this technique. In the present study, three different powder compositions (FAl-23SiC, FAl-46SiC, FAl-71SiC) obtained by mixing Al and SiC powders were cold sprayed on aluminum substrates. The volume percentage and the average size of the SiC particulates in the cold sprayed coatings were estimated and found to be 23%, 47% and 52% for FAl-23SiC, FAl-46SiC and FAl-71SiC feedstocks, respectively. Effects of percentage and size of the SiC particulate retained in the composite coatings on the mechanical properties and the sliding wear performance were studied at different sliding conditions in the as-sprayed and heat treated conditions. The results were comprehensively analyzed and found to correlate well with the microstructure of the coatings. •Correlation between fraction of SiC particulates in the cold sprayed Al-SiC MMC coatings and their mechanical properties was carried out.•Effect of heat treatment on the mechanical properties and wear performance of MMC coatings was studied comprehensively.•The best mechanical and wear properties were achieved for the heat treated coatings with 52 vol% of SiC particulates.