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

Abstract

The aim of this work is to explore the feasibility of the computer aided thermal analysis as a tool for SiC p content quantification in molten Al–Si/SiC p composites. This technique was applied to three cases of interest: (1) the metal matrix alloy A356, without SiC p particle reinforcement, (2) A356/8% SiC p MMC and (3) A356/18% SiC p MMC. Tests were performed in order to identify, within the commonly used thermal analysis parameters, the parameters that could be used for SiC p content quantification. In this regard, the parameters: eutectic temperature, T EG, and local solidification time, t S, show clear trends and low dispersion in their changes as functions of SiC p content. It is found that an increase in SiC p content produces a statistically significant increase of T EG and a decrease of t S. The behavior of t S may be explained as a result of the decrease of the latent heat released during solidification as the SiC p 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 SiC p content, if the local solidification time is the parameter used to quantify the particle content.