High-Pressure Die Casting of Al-Ce-La-Ni-Fe Alloys

The effects on phase equilibria of La and Fe additions to the Al-Ce-Ni-based alloy system are explored under high-pressure die casting conditions. The addition of La to Al-Ce-Ni-based alloy system only reacts with Ce synergistically to promote the formation of the Al11(Ce,La)3 intermetallic phase as predicted by CALculation of PHAse Diagrams (CALPHAD) and verified experimentally. High Fe additions react with Ni to form the Al9FeNi intermetallic phase, which is an additional eutectic former. The targeted co-precipitation type eutectic morphology is achieved in the alloys studied. Additional coarse particles of Al11(Ce,La)3, present in the alloys studied and not predicted by CALPHAD, are attributed to possible inclusions of Ce and La oxide, present in the mischmetal feedstock used. Both alloys exhibit exceptional mechanical stability after 10 hours at 400 degrees C due to the stability of the phases formed during solidification. The alloy with high Fe additions possessed better mechanical properties after heat treatment based on the higher eutectic content and more substantial improvement to the morphology of secondary phases after treatment.