# Effect of Replacement of Ni by Ta on Glass-Forming Ability, Crystallization Kinetics, Mechanical Properties, and Corrosion Resistance of Zr–Cu–Al–Ni Amorphous Alloys

## TL;DR

Replacing Ni with Ta in Zr–Cu–Al–Ni amorphous alloys improves their glass-forming ability, mechanical strength, and corrosion resistance.

## Contribution

The study introduces Ta as a substitute for Ni to enhance the properties of Zr-based bulk metallic glasses.

## Key findings

- Adding Ta increases the supercooled liquid region and critical diameter of the alloy.
- Ta improves mechanical properties, with yield strength reaching 1900 MPa and plastic strain exceeding 2.6%.
- Ta reduces corrosion current density and increases corrosion potential in different solutions.

## Abstract

In this study, bulk metallic glasses (BMGs) of Zr56Cu23Al10Ni11-xTax (x = 0, 0.5, 1, 1.5, 2, and 2.5 at.%) were prepared by copper mold suction-casting. The glass-forming ability, mechanical properties, crystallization kinetics, and corrosion resistance of the as-obtained amorphous alloys were all investigated. Experimental results showed enhanced forming ability of amorphous alloys in the presence of small amounts of Ta element. By adding appropriate amounts of Ta, the supercooled liquid region of bulk metallic glass increased from 64 K to 73 K. The critical diameter of the alloy rod at x = 1, 1.5 rose from 5 mm to 6 mm. The addition of Ta also reduced the sensitivity coefficients of the amorphous alloys to the heating rate during crystallization, while other quantities, like Eg, Ex, and Ep, all incremented. Thus, the addition of Ta declined the temperature sensitivity of amorphous alloy systems. This also increased the energy barrier required for atom rearrangement, nucleation and growth, as well as greatly enhancing the stability of the systems. At 2% Ta content, the plastic strain of the amorphous alloy exceeded 2.6%, and yield strength reached 1900 MPa. In sum, the mechanical properties of the amorphous alloys after the addition of Ta element obviously improved when compared to the original alloy. As Ta content raised, the corrosion current densities of BMGs in different corrosion solutions gradually decreased, while the corrosion potential gradually increased.