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Mg 58 Cu 31 Gd 11 and Mg 65 Cu 25 Gd 10 alloys were synthesized via two processing routes, injection casting and melt spinning. The diameter of the injection-cast bars was 4 mm in diameter. The XRD results obtained for the Mg 58 Cu 31 Gd 11 are nearly identical to those for the Mg 65 Cu 25 Gd 10 , showing amorphous-like broad characteristic peaks. All the four characteristic temperatures, T g , T x , T m and T l , of the Mg 65 Cu 25 Gd 10 are essentially lower than those of Mg 58 Cu 31 Gd 11 , for both injection-cast rods and melt-spun ribbons. The glass forming abilities of the Mg 65 Cu 25 Gd 10 are similar to those of Mg 58 Cu 31 Gd 11 , for both injection-cast rods and melt-spun ribbons, indicated by T rg = 0.60 and γ = 0.42. The average microhardness of the Mg 65 Cu 25 Gd 10 is 2.41 GPa and 2.27 GPa for injection-cast bars and melt-spun ribbons, respectively, which are significantly lower than 2.84 GPa and 2.49 GPa of the Mg 58 Cu 31 Gd 11 . The nanohardness at the maximum load from the multiple loading is 3.5 GPa for Mg 65 Cu 25 Gd 10 , which is lower than 3.9 GPa for Mg 58 Cu 31 Gd 11 . The curves of load vs. the depth obtained from the nanoindentation tests all show stepwise behavior due to the pop-in events, and the step width increases as the indentation rate decreases. The modulus at the maximum load from the multiple loading obtained from the nanoindentation tests is 64.9 GPa for Mg 65 Cu 25 Gd 10 , which is lower than 70.7 GPa for Mg 58 Cu 31 Gd 11 . The fracture stress and strain of the Mg 65 Cu 25 Gd 10 BMG rod at room temperature are 490 MPa and 3%, respectively, smaller than those of the Mg 58 Cu 31 Gd 11 BMG rod, 548 MPa and 3.2%, respectively. The Mg 58 Cu 31 Gd 11 BMG rod is stronger at room temperature, and also shows higher yield stress and less deformable at elevated temperature, than the Mg 65 Cu 25 Gd 10 BMG rod. |
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