The Effect of Revert Percentage on the Melt Quality and Mechanical Properties of Aluminum-SiC Composites

摘要

The melt processing of metal matrix composites includes stirring to keep the reinforcement particles in suspension. This stirring action may introduce additional air into the melt, which has a detrimental effect on oxide levels. This condition is compounded by the addition of oxide rich revert and the difficulty of effectively cleaning the MMC alloys. Most foundries control the problem by either limiting the amount of revert used or using time consuming and expensive cleaning techniques that may effect reinforcement levels. This paper compares alloy microstructures and mechanical properties of castings made from melts prepared with various levels of revert (clean gates, risers and scrap casting). Recommendations for optimum revert additions are made based on casting quality requirements.