Assessment of thermal conductivity for FCC Al-X (X=Zn, Mg) and Al-Zn-Mg alloys: Experiments and modeling

Abstract

Thermal conductivity is one of the critical thermophysical properties for Al alloys. However, in comparison with mechanical properties, fewer studies focused on investigating thermal conductivity for Al alloys such as Al-Zn-Mg and its sub-systems. This study aims to combine experiments and modeling to assess thermal conductivity of FCC Al-Zn, Al-Mg and Al-Zn-Mg alloys. FCC Al-Zn, Al-Mg and Al-Zn-Mg alloys were first designed by CALPHAD (Calculation of PHAse Diagram) method. The alloy samples were prepared using the vacuum induction melting furnace, and their compositions and structures were validated via ICP (Inductively Coupled Plasma), XRD (X-ray diffraction) and SEM (Scanning Electron Microscope). Subsequently, LFA (Laser Flash Analysis) was applied to measure thermal conductivity of the presently prepared samples at 298, 348, 398, 448 and 498 K. Moreover, a novel model incorporated in CALTPP (CALculation of ThermoPhysical Properties) software was implemented for evaluating thermal conductivity of FCC Al-Zn, Al-Mg and Al-Zn-Mg alloys from 298 K to 498 K. All the deviations between the model-evaluated thermal conductivity and measured ones are within ±10 %, indicating that the present calculations are reliable. Furthermore, this work used this developed model to predict composition-dependent and temperature-dependent thermal conductivity for FCC Al-Zn, Al-Mg and Al-Zn-Mg alloys. The present work provides an effective way to investigate thermal conductivity for single-phase solid solutions combining experiments and modeling.