Structural Stability and Amorphization Transition in the Ni–Ti System Studied by Molecular Dynamics Simulation with an n-Body Potential

An n-body Ni–Ti potential is derived and verified to be capable of reproducing some physical properties in the Ni–Ti system. Applying the constructed potential molecular dynamics simulations of solid-state reaction in the Ni–Ti multilayers reveal that the growth of an amorphous interlayer follows a linear t correlation at the very beginning and then shifts to exactly a t 1/2 law and that a sharp semi-coherent interface serves as a nucleation barrier, preventing the interfacial reaction at a temperature up to 873 K. Moreover, the asymmetric growth of amorphous interlayer is found to originate from the sequential disordering of constituent metals by dissolving its partner atoms beyond its maximum allowable solubility, which is named as a solubility criterion. In addition, the calculated maximum solid solubilities also predict that an intrinsic glass forming range in the Ni–Ti system is from 15 to 62 at.% of Ni, which is in good agreement with the experimental results.