Phase transitions in Al_3Ca_8 and Al_(14)Ca_(13) intermetallic compounds induced by milling and annealing

摘要

The phase transformations occurring in mechanically milled and annealed tridinic Al_3Ca_8 intermetallic compound have been studied. The Al_3Ca_8 phase transforms initially to the nanostructured monoclinic Ali_4Ca-(13) intermetallic during milling. The Al_(14)Ca_(13) phase is metastable and transforms back to the AI_3Ca_8 compound during subsequent heating. The transformation starts at low temperature with the grain coarsening of the Al14Ca13 phase. At intermediate temperatures, the transformation from Al_(14)Ca_(13) to Al_3Ca_8 occurs. The sequence is completed at high temperatures with the grain coarsening of the Al_3Ca_8 phase.