Nanolayered diffusion couple technique for the reconsidering of the miscibility gap

TL;DR

This paper revisits the Cu-Ni binary phase diagram using a nanolayered diffusion couple technique, addressing previous uncertainties about the existence of a miscibility gap and discussing methodological challenges and phase diagram implications.

Contribution

It introduces a nanolayered diffusion couple method to reassess the Cu-Ni phase diagram and investigates the presence of a miscibility gap with considerations of strain and size effects.

Findings

Evidence of a miscibility gap in Cu-Ni system at certain temperatures

Discussion on strain and size effects on phase equilibrium

Validation of the nanolayered diffusion technique for phase diagram analysis

Abstract

Mysteries in binary phase diagram are still in existence, e.g., the case in Cu-Ni which is mutual miscible system, the question addressed that "Indirect experimental evidence indicates the presence of a miscibility gap in the fcc phase at a temperature somewhere between 450 and 923 K". Recently, author's group suggests new miscibility gap on Cupper-Nickel system by means of Secondary Neutral Mass Spectroscopy (SNMS) with nanolayered diffusion couple technique. Here we considered about problems in this technique, e.g., strain and size modified miscibility gap, equilibrium and its morphorogy, how to differentiate it, etc. Finally we discussed for justification of our procedure and phase diagrams on several binary alloys.