The Microstructure, Tensile Properties and Corrosion Resistance of Mg–Al–Sn–Zn Alloys Modified by Minor Ce Addition

Abstract

The microstructures, tensile properties and corrosion resistance of Mg–7.5Al–2Sn–1Zn (ATZ721) base alloys modified by minor cerium (Ce) additions (0.5, 1.0 and 2.0 wt. %) were investigated. Ce addition leads to the formation of Al₄Ce phase, reduces volume fraction of Mg₁₇Al₁₂ phase and refines the microstructures. Tensile tests demonstrated that Ce significantly improved the mechanical properties at room temperature (RT) and 175°C. The alloy with 1.0 wt.% Ce showed superior performance with an ultimate tensile strength (UTS) of 237 MPa, yield strength (YS) of 98 MPa and elongation to failure (E_f) of 16.7% at RT, representing 22%, 17% and 52% improvements over the base alloy, respectively. Corrosion resistance was notably enhanced, with the 1.0 wt.% Ce alloy exhibiting a corrosion rate of 1.8 mm/yr in a 3.5 wt.% NaCl solution, significantly lower than the base alloy’s 8.4 mm/yr.

Keywords:
Mg–Al–Sn–Zn; Ce; tensile properties; corrosion resistance; Al₄Ce