摘要 |
A squeeze formed aluminium alloy article, such as a piston, is formed with a re-entrant cavity (14) by locating an isostatically compacted salt core (10) in the mould cavity of the squeeze forming press prior to introduction of the molten metal therein. The core (14) is subsequently dissolved from the squeeze formed article to provide a corresponding shape to the article which does not require subsequent machining. |