Nanocrystalline structure and Mechanical Properties of Vapor Quenched Al-Zr-Fe Alloy Sheets Prepared by Electron-Beam Deposition

Abstract

Nanocrystalline Al-based ternary alloys with additions of Zr and Fe have been prepared by electron-beam deposition. The composition dependence of microstructures and mechanical properties has been investigated. Fine α-Al grains are observed and the grain size significantly decreases with the increase of Zr content. Al_95.3-Zr_4.0-Fe_0.7 and Al_96.5-Zr_2.8-Fe_0.7 alloys consist of α-Al containing the coherent meta-stable L1₂ precipitate. The addition of Fe, effectively refined the grain structure, increases hardness and improves the thermal stability of the meta-stable L1₂-Al₃Zr phase. Al_95.3-Zr_4.0-Fe_0.7 alloy exhibits remarkably high tensile strength both at room temperature and above 523 K, 817 MPa at room temperature, 536 MPa at 523 K and 434 MPa at 573 K, respectively. The microstructure of Al_95.3-Zr_4.0-Fe_0.7 alloy exhibits excellent thermal stability under prolonged annealing at 523 K.