Improvement of the thermal stability of Gd–Dy–Al–Co bulk metallic glass by the addition of high bulk modulus elements

A series of new heavy rare-earth based bulk metallic glasses with high thermal stability have been obtained by a copper mold casting method. Compared with the light rare-earth based bulk metallic glasses, these alloys have much higher glass transition temperature, crystallization temperature, and larger effective activation energy for glass transition and crystallization. It was found that the addition of high bulk modulus element Ge can further enhance the thermal stability of these alloys. These results confirm that the thermal stability is closely correlated with the bulk modulus of rare-earth based bulk metallic glasses, which is useful for guiding the composition design of the BMG alloys with high thermal stability.