Zr-Al-Co-Cu bulk metallic glasses for biomedical devices applications

Toxic element-free Zr-based bulk metallic glasses (BMGs) with a property combination of high glass-forming ability, ultrahigh strength and large room-temperature plasticity are useful as surgical devices materials. In the present work, the critical glass formation size (dmax), thermal glass stability and room-temperature mechanical properties of a series of Zr56.25Al18.75(Co1-xCux)25 (x = 0, 0.125, 0.25, 0.375, 0.5, at.%) alloys have been investigated. The Zr56.25Al18.75Co18.75Cu6.25 (x = 0.25) BMG alloy is found to combine a centimeter scale dmax with ultrahigh strength (σy = 2.05 GPa), high Young's modulus (E = 92.4 GPa) and large room-temperature plasticity (ɛP = 3.5%). Comparison of the property combination of various biomedical Zr-based BMGs suggests that the Zr56.25Al18.75Co18.75Cu6.25 BMG can be a promising surgical devices material. The thermal and mechanical stabilities of these BMG alloys are qualitatively understood with the electron concentration and split d-band electronic structure stabilization mechanisms.