Effects of annealing on Al–Si coating synthesised by mechanical alloying

ABSTRACT

An Al–Si composite coating was synthesised on Ti–6Al–4 V alloy substrate by means of mechanical alloying. The as-synthesised coating had a composite structure. The effects of annealing treatment on the microstructure, the mechanical properties and the oxidation resistance of coating were investigated. The increase in annealing temperature was conductive to the formation of multilayered structure of the coating. The formation processes of the layers at different annealing temperatures were discussed. The coating annealed at 800°C had intermetallic layers, which improved the microhardness and wear resistance of the coating. The microhardness of the coating annealed at 800°C reached more than three times of the substrate microhardness. In addition, the coating annealed at 800°C had a thick inner protecting layer, which could retard the inward diffusion of oxygen during oxidation. The annealing of the coating at 800°C could improve the mechanical properties and oxidation resistance of the coating.

KEYWORDS:

• Al–Si coating
• mechanical alloying
• annealing treatment
• microhardness
• friction and wear resistance
• high-temperature oxidation resistance

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (grant no. 51475232); funding for Outstanding Doctoral Dissertation in NUAA (grant no. BCXJ14-09) and a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions.