Description of millisecond Ohmic heating and forming of metallic glasses

摘要

A quantitative description of the millisecond capacitive discharge heating and forming process built on a finite-element simulation platform is introduced. The platform incorporates thermodynamic and rheological models that extend beyond the supercooled liquid regime accessible by conventional calorimetry and rheology, accessing the regime that has just recently been uncovered via millisecond Ohmic heating. For the first time, a description of the dynamic glass transition is introduced and incorporated into the platform. The platform accurately simulates the process evolution and the thermodynamic and rheological response of the metallic glass, providing excellent agreement with experiments. Features such as the rapid temperature response, a dynamic glass-transition accommodated by a broad enthalpy recovery, a remarkable temperature and deformational uniformity, and an enthalpy trend that validates the adiabatic constraint, are accurately simulated. The platform is considered a useful tool for modeling the dynamic response and process evolution of metallic glasses under rapid uniform heating.