Development of Ni- and Cu-Free Zr-based bulk metallic glasses for biomedical applications

Two Ni- and Cu-free bulk metallic glasses (BMGs) of Zr65Pd 17.5Fe10Al7.5 and Zr65Pd 12.5Ag5Fe10Al7.5, with a critical casting diameter of 6mm and a compressive strength above 1500 MPa, were developed. While the Zr65Pd17.5Fe10Al 7.5 alloy showed little plastic strain before fracture, the Zr 65Pd12.5Ag5Fe10Al7.5 alloy exhibited much larger plasticity by the relatively stable, intermittent propagation of the major shear band under compression. This unusual plastic deformation behavior was interpreted on the basis of the contribution of the icosahedral shortrange order. Potentiodynamic polarization tests revealed that the Zr65Pd12.5Ag5Fe10Al 7.5 alloy has a higher corrosion resistance than the Zr 65Pd17.5Fe10Al7.5 alloy in phosphate buffered saline at 37°C. X-ray photoelectron spectroscopy analysis revealed that the passive film of Zr65Pd12.5Ag5Fe 10Al7.5 alloy consisted mostly of ZrO2, which may be responsible for the excellent corrosion resistance of this alloy. Ni- and Cufree BMGs with a critical diameter of 6 mm, together with enhanced mechanical properties and corrosion resistance, may be promising in biomedical applications.Department of Industrial and Systems Engineerin