Effect of remelting treatment on glass forming ability of RE (Gd, Sm)56Al26Co18 alloys

The bulk metallic glasses (BMGs) were prepared by a copper mold suction casting method, denoted by Gd56Al26Co18 (1) and Sm56Al26Co18 (1). Then, the obtained metallic glasses mentioned above were remelted and injected to copper mold, and the metallic glasses were prepared by remelting, denoted by Gd56Al26Co18 (2) and Sm56Al26Co18 (2). The glass forming ability and thermal expansion behavior were investigated by X-ray diffraction (XRD), differential scanning calorimetry (DSC), dilatometer and high resolution transmission electron microscopy (HRTEM). The results showed that the remelting treatment can improve the glass forming ability of the alloys. In addition, it was found that the average thermal expansion coefficients of the BMGs prepared by remelting were smaller than the BMGs prepared by first-time melting for Gd56Al26Co18 and Sm56Al26Co18 alloys, which indicated the remelting treatment can enhance the thermal stability of the Gd56Al26Co18 and Sm56Al26Co18 BMGs.