Addition of holmium and erbium and hot-rolling effects on the microstructure and mechanical properties of Mg–Li based alloys

Abstract

Magnesium–Lithium Rare Earth based alloys being ultra-light and strong offer suitability for wide industrial applications. This is because they form stable strengthening phases and activate extra deformation modes under optimized conditions. Effects of introducing Holmium (Ho) and Erbium (Er) elements in Mg–8Li–3Al alloy followed subsequently by aging and hot-rolling deformation were studied. The alloys microstructure morphology was examined using scanning electron microscope (SEM) and energy dispersive spectroscopy (XEDS). Phase analysis depicted the presence of both α-and β-phases alongside intermetallic compounds. Mechanical tensile test results showed increased Yield Strength (YS) and Ultimate Tensile Strength (UTS) on introduction of rare earth elements with optimized thermo-mechanical treatment. The as-cast Mg–8Li–3Al alloy exhibited an elongation of 9.5%. Thermo-mechanically treated Mg–8Li–3Al–3Er and Mg–8Li–3Al–3Ho alloys exhibited an increased optimal elongation of 19.1 and 21.4% respectively. Synergistic effects of adding Holmium and Erbium elements, with aging and hot-rolling deformation enhanced the alloys mechanical properties through work hardening and solution strengthening mechanisms.