Metastable Al-Nd-Ni and stable Al-La-Ni phase equilibria

Fast cooling leads to the formation of metastable phase equilibria in the A l-rich part of the Al-Nd-Ni system. The metastability is characterized by a suppressed formation of the ternary tau (1) phase. The stable Al-La-Ni sys tem is similar to the Al-Nd-Ni system but without the existence of a tau (1 ) phase. For comparison, this system is investigated. The results are repre sented as isopleths, liquidus surface projections, and reaction schemes. A fine-grain ternary eutectic morphology with enhanced hardness can be produc ed by rapid cooling in both ternary systems; the ideal chemical composition of this morphology depends on the cooling rate.