Synthesis and electrochemical behaviour of TiC- and B4C-reinforced Al-based metal matrix composite

Abstract

Aluminium (Al)-based metal matrix composites were developed with titanium carbide (TiC) and boron carbide (B4C) materials as reinforcement. The weight percentages of titanium carbide (1.5%) and boron carbide (0.5%) powder were maintained throughout the process of composite development. Composite process parameters such as powder compaction pressure, sintering temperature and time were varied in different combinations. The prepared composites were mechanically evaluated and metallurgically investigated for their quality. Further, the samples were subjected to electrochemical analysis to study their behaviour in 3.5% sodium chloride (NaCl) solution. From the experimentation, the corrosion potential and current density were measured. Subsequently, the corrosion rate (mm/year) of the material was calculated through its Tafel plot. The composite processed at a sintering temperature of 630°C for a duration of 135 min had higher corrosion resistance, with a minimum corrosion rate of 1.699 mm/year. The electrical resistance also increased over the exposed surface with a minimum current density of 0.15 mA/cm2. Scanning electron microscopy and energy-dispersive spectroscopy (EDS) were used to determine the metallurgical quality of the exposed surface. The oxide formation was observed on the exposed surface in the process of corrosion. The element aluminium and oxygen were found on the surface which denotes that the Aluminium oxide formed on the exposed surface. From the results, a discussion is presented confirming the influence of composite powder processing parameters.