Carbon ion implantation into aluminium: Mechanical and tribological properties

Abstract

Aluminium carbide nucleation and growing kinetics is correlated to the mechanical properties (hardness and elastic modulus), and to the friction coefficients as a function of carbon ion implantation parameters on aluminium. The microstructure of the modified surface was studied by: a) Elastic Recoil Detection Analysis (ERDA), b) Grazing Incidence X-ray Diffraction analysis (GIXRD) and c) Raman spectroscopy. Hardness and elastic modulus profiles were measured by instrumented nanoindentation technique. Pin-on-disc technique in reciprocal scratch mode was employed to obtain the friction coefficient profile. For low carbon fluences (≤2 × 10 17 C + cm − 2 ) small size (≈ 4 nm) embedded Al 4C 3 precipitates were produced. Higher carbon fluences create an amorphous-like structure. Implantations performed at high substrate temperatures can produce big size precipitate (≈ 40 nm). Surface hardness increases as a function of carbon fluence resulting in values of about 6 GPa (20 times Al bulk value). The hardening mechanisms are associated with dislocations to precipitates bowing and/or cutting processes. Implantation parameters ruled the mechanical properties. Tribological responses are more difficult to correlate to the ion implantations conditions. However, wear is reduced when highly disordered C–C cluster are present.