Formation of a new Mg-Cu-Ni-Gd Bulk Metallic Glass: Effects of Rare Earth on Glass-forming Ability of Mg-TM-RE Bulk Metallic Glasses

A new Mg65Cu18Ni6Gd11 bulk metallic glass (BMG) with high level of Ni content, exhibiting glass-forming ability (GFA) of 6 mm, was fabricated by copper mold casting. The compressive strength and plasticity of the Mg65Cu18Ni6Gd11 BMG were 938 MPa and 0.14%, respectively. The composition design of the Mg65Cu18Ni6Gd11: BMG with enhanced GFA had succeeded simply using Gd substituting Y in the Mg65Cu18Ni6Gd11 BMG, which was a result of a comparison on the GFA between the Mg-TM-Gd and Mg-TM-Y BMGs (TM: transition metals). Compared to the Mg-TM-Y BMGs, the Mg-TM-Gd BMGs exhibited improved GFA, which was demonstrated to be mainly attributed to the more negative amorphous formation enthalpy resulting from Gd substituting Y. The effects of rare earth (RE) elements on the GFA of Mg-TM-RE were discussed. This work may suggest an easy way for developing new Mg-based BMGs with improved GFA by rare earth (RE) design.