Bulk metallic glass formation in Zr-Cu-Fe-Al alloys

摘要

We have discovered a series of bulk metallic glass-forming alloys of composition (Zr_xCu_(100-x)_(80)(Fe_(40)Al_(60)_(20) with x=68-77 and. have investigated them by x-ray diffraction, small-angle neutron scattering, and differential scanning calorimetry. All of these alloys exhibit a calorimetric glass transition temperature of 670 K < T_g < 687 K and a large undercooled liquid region of widths 73-86 K. The best glass-forming ability is obtained for x ≈ 72.5, i.e., for the alloy Zr_(58)Cu_(22)Fe_8Al_(12). In rod shape this alloy has a critical casting thickness of 13 mm, as verified by detailed casting experiments, while alloys with x=68 and 77 can still be cast to a thickness of 5 mm. Furthermore, the region where glassy samples with a thickness of 0.5 mm can be prepared extends from x=62-81. The best glass-former, Zr_(58)Cu_(22)Fe_8Al_(12), has a tensile yield strength of 1.71 GPa and shows an elastic limit of 2.25%. This new class of Ni-free Zr-based alloys is potentially very interesting for biomedical applications.