The full potential of the semi-solid forming process (with its requirement for a uniform, spherical primary phase throughout) has not been realized due to difficulties in developing technology for the production of large inexpensive feedstock. Furthermore, even with existing semi-solid metal systems, narrow process windows and alloy chemistry restrictions increase process costs and limit performance attributes. This project will develop production technology for semi-solid forming utilizing new proprietary feedstock metals. The approach offers an intrinsic, highly uniform, spherical solid phase, without electromagnetic or mechanical shearing. The Phase I project successfully demonstrated that large diameter feedstock with a uniform permanent spherical solid phase, could be produced at low cost. Also, the semi-solid forming process window was expanded and semi-solid material was formed with substantially enhanced physical and mechanical properties compared to existing semi-solid forming materials. The Phase II project will produce 6-inch diameter billets suitable for semi-solid forming (SSF) and design, fabricate, and test aluminum engine components. Primary billet processing costs, SSF costs, heat and mass transport during SSF, and material behavior will be modeled. Both basic and application-specific microstructural/mechanical/thermal property databases will be developed. Finally, 4-inch billet SSF capability will be established.
Commercial Applications and Other Benefits as described by the awardee: The semi-solid forming process should apply to high volume, cost sensitive components and components with higher performance requirements. The total volume of semi-solid formed components should increase in such applications as automotive thermal management and brake components, military engine components, electronic packaging, and precision equipment.
