Effects of additional element on the glass forming ability and corrosion resistance of bulk Zr-based amorphous alloys

Abstract

By using the real-place recursion method， bulk Zr-based amorphous alloys with effects of additional element Nb，Ta，Y，La on the glass forming ability and corrosion resistance were studied. The atomic structure model of primary precipitation phase Zr2Ni in Zr-based amorphous alloys were constructed by computer programming. The icosahedron cluster in Zr-based amorphous alloys was simulated by using the icosahedral cluster in Zr2Ni primary precipitation phase. The local density of states (LDOS) curves of Zr，Ni (before substitution) and alloying elements (after substitution) at the center or the corner of icosahedron cluster， the total bond order integral between the centered Ni atom and it's nearest neighbor (Zr，Nb，Ta，Y，La) in the icosahedron cluster， and the Fermi energy levels of the icosahedron cluster (before and after alloying elements' substitution) were calculated. The LDOS calculation results showed that the Cu atom occupies the center site of the icosahedral cluster， Nb， Ta， Y， La atoms occupy the site of Zr atom at the corner in Ni-Zr icosahedral clusters. The bond order integer calculation results suggest that Y increases the glass forming ability (GFA) of Zr-base amorphous alloys， Nb and Ta decreased the GFA， and La has little influence on the GFA. The calculated Fermi energy levels suggest that Nb， Y， La make Zr-based amorphous alloys easy to be passivated and improve the Zr-based amorphous alloys corrosion resistance. Ta has little influence on the corrosion resistance of the alloys. Therefore， Y and La are most effective on improving the GFA and corrosion resistance of Zr-based amorphous alloys. By addition of small amounts of Y and La， new bulk amorphous alloys with good corrosion resistance can be prepared.