Defect control on Al castings for excellent quality and improved performances through novel Rheocasting processes

摘要

Commonly, components of complex shapes are prepared by casting or by forging processes, in relation to the economical and performance require. Casting technologies versus forging are more competitive from economical point of view, while forging is able to guarantee the best performances, thanks to the highest soundness. Castings can be affected by defects like voids or cavities, inclusions and oxides. Semi-solid processes can reduce the existing gap between casting and forging and during such a processes there are the opportunity to better control the defect level. In this paper the attention will be focused on some very promising squeeze and rheocasting processes, which have been recently developed. Particular importance will be dedicated to the study and discussion of the possible causes of the defects related to their origin and mechanism, in order to allow their fully control and to attain the production of high performance and reliable complex shape components at competitive costs.