Microstructure refinement and its effect on specific strength and bio-corrosion resistance in ultralight Mg-4Li-1Ca (LC41) alloy by hot rolling

Mg-4Li-1Ca (LC41) alloy was hot rolled at 300 °C, which resulted in refinement of the grain size from 100 μm to 5 μm by recrystallization in the presence of fine uniformly dispersed eutectic (α-Mg + Mg2Ca). Evidence of profuse deformation twinning in the microstructure suggested twinning to be the important mode of deformation in the present material. Room temperature tensile tests of the alloy at a strain rate of 10−4 s−1 exhibited substantially high specific strength of 142 kN m/kg owing to its low density and combined effect of grain boundary strengthening and dispersion strengthening in the presence of Mg2Ca phase. LC41 alloy also showed an increase in the overall bio-corrosion resistance (Rp = 0.266 kΩ cm2) in simulated body fluid (SBF) as a result of a change in the corrosion mechanism from localized to uniform corrosion. The reported combination of excellent properties is a clear indication that the new ternary alloy LC41 has a significant potential for use in lightweight structural and biomedical applications.