Temperature Dependence of Lattice Misfit in Determining Microstructural Evolution of High Temperature High Strength Aluminium Alloys—A 3D Phase-Field Study

Abstract

One of the recent advancements in the field of high temperature high strength aluminum alloys is the development of the Al-Sc-Zr alloy. The addition of Sc and Zr in the Aluminium matrix results in trialuminide precipitation that imparts excellent coarsening resistance, making the alloy suitable for high-temperature application. In the early stages of solid–solid phase transformations, the coherent microstructure is developed by maintaining the continuity between lattice planes and directions along the interface. These misfit strains significantly influence the shape and growth of trialuminides. The temperature dependency of misfit strain, which is often neglected in the theoretical simulations of precipitate phases, is considered in the present work to investigate microstructural evolution and resulting strain and concentration field distribution during trialuminide precipitation using the phase-field method. Also, an assessment of the precipitation kinetics during Al₃X (X = Sc, Zr) growth in the Al matrix with the help of particle size and energy variation-time graph is also done to get an insight into the precipitation mechanism.