Effect of Nb on Transformation Kinetics and Mechanical Properties in Zr-Al-Ni-Cu Metallic Glasses

Abstract

The effect of Nb addition on the nucleation and grain growth behaviors has been investigated in the monolithic Zr 65 Al 7:5 Ni 10 Cu 12:5 Nb 5 metallic glass. Nb has been well-known as an element for icosahedral quasicrystalline (QC) phase formation in the primary crystallization stage as well as for improving mechanical properties and corrosion resistance. The grain growth rate of the QC phase at near the crystallization temperature is 1:2 Â 10 À9 m/s, which is approximately 10 times smaller than that of the primary fcc Zr 2 Ni phase in the Zr 65 Al 7:5 Ni 10 Cu 17:5 metallic glass. In contrast, nucleation rate increases drastically by Nb addition. It can be calculated as 1:2 Â 10 21 /m 3 s, which is approximately 10 5 times larger than that of the Zr 65 Al 7:5 Ni 10 Cu 17:5 alloy. The results indicate that Nb is a very effective element for controlling grain growth and nucleation rates. Good plasticity is exhibited in the as-cast alloy, however, it is lost drastically even after the structural relaxation as well as the QC precipitation. Such significant change may be attributed to the local ordering and/or phase separating tendencies by a positive chemical affinity of the Zr-Nb pair.

Thermal stability and mechanical properties of Cu46Zr46Ag8 bulk metallic glass and its composites

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Effect of Pulse Frequency on Phase Composition and Properties of Amorphous Zirconium Alloy Micro-arc Oxidation Coating

“…In the amorphous alloy system, due to the glass forming ability of the zirconium-based amorphous alloy [1]. The large supercooled liquid region, and the excellent mechanical properties [2], it has attracted the attention of the materials staff [3][4][5][6]. At present, the research of amorphous alloys has become a research hotspot in the field of materials science.…”