Silicon particle distribution in the in-situ Al-Si base functionally gradient material fabricated by centrifugal casting

摘要

A trial make Al-Si base multi-functionally gradient materials by means of centrifugal casting has been performed. The aim of this trial is to make an in-situ cylindrical composite in which the outer surface is enriched with Al of high heat conductivity, and the inner surface is abounded with Si-particles of high melting point. As the consequence, the fine Si-particles disperse to the inner surface, as the rotation frequency of a mold increases. However, the Si-particles do not necessarily tend to distribute gradiently along the thickness direction of the cylindrical composite. This might be because the precipitation process of Si is complicatedly influenced by the centrifugal force. The rotation axis component of molten metal flow also acts as reducing the population of Si-particles at the inner surface because of carrying them to the both edges of the cylindrical composite.