Structure-induced microalloying effect in multicomponent alloys

•Microalloying Zr in the NiNb alloy leads to the enhanced glass-forming ability.•We propose a new parameter which counts fraction of the five-connected shell atoms.•Such structural parameter is closely associated with the glass-forming ability.•It is a new criterion to evaluate the GFA of metallic glasses from the atomic structure perspective.

In this work, the microalloying effect on glass-forming ability (GFA) has been investigated from the structural aspect, by performing synchrotron radiation X-ray diffraction and absorption measurements coupled with simulations in the NiNbZr ternary system. By sorting out the preferred Voronoi clusters, we propose a new structural parameter which counts the fraction of the five-connected shell atoms in clusters and find it is strongly associated with the GFA. In particular, this structural parameter has the highest value in a composition where the best GFA is achieved. The present work provides an in-depth understanding of microalloying-induced high GFAs in multicomponent alloys.

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