Liquid phase separation in Gd–Ti and Gd–Zr melts

Liquid phase separation in two binary melt systems, Gd–Zr and Gd–Ti, related to phase separated metallic glasses are investigated by electromagnetic levitation experiments. Gd–Ti samples quenched onto a copper chill substrate from temperatures below the binodal line exhibit typical coarse phase separated microstructures, assigning melt immiscibility. The miscibility gap of Gd–Ti melts extends at least from 10 to 80 at.% Gd, much wider than reported previously. The critical temperature is about 1580 °C at Gd20Ti80. In the Gd–Zr system no indication of a stable liquid miscibility gap was detected. However, melt droplets quenched from the undercooled state exhibit concurrent coarse Gd and Zr primary phase constituents suggesting a metastable miscibility gap.