Thermal stability of RE5(SixGe1−x)3 plates in RE5(SixGe1−x)4 alloys, where RE = Gd and Ho

The stability of RE5(SixGe1−x)3 plates was studied through electron microscopy examination of as-cast and annealed Gd5Ge4 single crystal samples. Thermal annealing of samples at 1200 °C showed instability of the plates and a sluggish dissolution into the matrix. Scanning electron microscopy of Ho5(Si0.8Ge0.2)4 samples that had undergone laser surface melting indicated that the resulting rapid solidification of the melt pool suppressed precipitation of the characteristic 5:3 thin plates.