Quantification of the SiCp content in molten Al–Si/SiCp composites by computer aided thermal analysis

The aim of this work is to explore the feasibility of the computer aided thermal analysis as a tool for SiCp content quantification in molten Al–Si/SiCp composites. This technique was applied to three cases of interest: (1) the metal matrix alloy A356, without SiCp particle reinforcement, (2) A356/8% SiCp MMC and (3) A356/18% SiCp MMC. Tests were performed in order to identify, within the commonly used thermal analysis parameters, the parameters that could be used for SiCp content quantification. In this regard, the parameters: eutectic temperature, TEG, and local solidification time, tS, show clear trends and low dispersion in their changes as functions of SiCp content. It is found that an increase in SiCp content produces a statistically significant increase of TEG and a decrease of tS. The behavior of tS may be explained as a result of the decrease of the latent heat released during solidification as the SiCp content is increased, such as was indicated by the latent heat data obtained from Newton thermal analysis (NTA) applied to the experimental cooling curves. A simplified analysis of the experimental results indicates that, for the experimental conditions used in this work, the best resolution that could be expected from this method is ±1.3 vol.% of SiCp content, if the local solidification time is the parameter used to quantify the particle content.