New MgLi based Mg-Li-Cu-(Y, Gd) BMGs: Preparation, glass forming ability and mechanical properties

Through calculating the forming enthalpy by Modified Miedema Model, new MgLi-based bulk amorphous alloys Mg-Li-Cu-(Y, Gd) have been successfully designed and fabricated by conventional copper mold injection casting method. The X-ray diffractometer and differential scanning calorimeter results indicated that the as-cast Mg-Li-Cu-(Y, Gd) alloys were fully amorphous structure after casting to critical diameter as large as 4 mm and 2 mm. The experimental results also proved that with increasing Li content (3 at.%-8 at.%), the supercooled liquid region temperature of Mg-Li-Cu-(Y, Gd) alloys gradually decreased accompanying the reduce of glass forming ability. It was also found that appropriate addition of metal Li effectively increased the fracture strength and elastic strain and reduced their corresponding densities. The maximal fracture strength reached 468 MPa and 478 MPa, respectively, which were much higher than normal MgLi-based crystalline alloys (~ 300 MPa).