Elastic Field Evolution in Al-X (X=Sc,Zr,Er) Alloy During Heat Treatment, Insights from 3D- Multi Phase Field Study

Microstructural evolution and resulting stress, strain, and concentration field distribution during Al3X (X=Sc, Zr, Er) precipitation in Al matrix are investigated in this work using the 3D-multi phase-field method. Depending on the heat treatment, modulus mismatch, lattice parameter mismatch, and interfacial free energy, precipitate developed to rhombicuboctahedron, and near cuboidal morphologies. The composition distribution and AlAl3X transformation driving force map identified a difference in precipitation kinetics for each alloy. The precipitation mechanism in the three systems is analysed in detail with temporal evolution plots of energy components during phase transformation. Al3Er precipitate exhibits the highest growth rate due to Er's high diffusivity and significant lattice parameter mismatch in the Al-Er system. The system has a high chemical and elastic driving force for particle growth, thus attaining quasi-static equilibrium at a relatively lower temperature and time. Therefore, this system observes high magnitude stress, strain, and strain energy field around the Al matrix. The theoretical simulation results obtained from the present study will benefit Aluminium multicomponent alloy design for high strength applications.