| Abstract Scope |
The sharp-edge Fe-rich intermetallic phases deteriorate the mechanical properties of recycled Al alloys, many attempts, such as alloy elements, grain refinement and cooling rate, have been made to modify the morphology of these phases. In this presentation, synchrotron X-ray radiography had been used to in-situ observation the growth dynamic of Fe-rich phases in Al alloys during solidification. The results showed that Al-5Ti-1B grain refiner, as well as the cooling rate, both reduced the size and number of primary Fe-rich phases. Ti-containing solutes in the melts inhibit the diffusion of Fe atoms and the Al3Fe twins produce re-entrant corner on the twin boundaries along the growth direction. Moreover, the TiB2 provides possible nucleation sites for Al6Fe phases. Also, high cooling rate inhibit the growth of primary Fe-rich phases. This study provide visible evidence to clarify insight into the nucleation and growth mechanisms of Fe-rich phases influenced by Al-5Ti-1B and cooling rate. |