Phase selection and microstructure of slowly solidified Al-Cu-Fe alloys

The search for effective methods to fabricate bulk single-phase quasicrystalline Al-Cu-Fe alloys is currently an important task. Crucial to solving this problem is to understand the mechanisms of phase formation in this system. Here we study the crystallization sequence during solidification as well as the conditions of solid phase formation in slowly solidified Al-Cu-Fe alloys in a wide range of compositions. We have also constructed concentration dependencies of undercoolability by differential thermal analysis method. These experimental results are compared with data on chemical short-range order in the liquid state determined from ab initio molecular dynamic simulations. We observe that the main features of interatomic interaction in the Al-Cu-Fe alloys are similar for both liquid and solid states and they change in the vicinity of i-phase composition. In the concentration region, where the i-phase is formed from the melt, both the undercoolability and the crystallization character depend on the temperature of the melts before cooling. © 2019 Elsevier B.V.This work was supported by supercomputer of IMM UB RAS and computing resources of the federal collective usage center Complex for Simulation and Data Processing for Mega-science Facilities at NRC “Kurchatov Institute” Russian Science Foundation (grant RNF 18-12-00438 ). The experimental study was perfomed using equipment of the Shared Use Centre of Physical and Physicochemical Methods of Analysis and Study of the Properties and Surface Characteristics of Nanostructures, Materials, and Products, UdmFRC UB RAS. AIMD simulations have been carried out using ”Uran” http://ckp.nrcki.ru