Ultra-strong Mg alloy with nano-grain structures produced by a high-throughput magnetron co-sputtering method for the full chemistry spectra

Recent advances in high-throughput fabrication under non-equilibrium conditions have enabled the simultaneous preparation of many multicomponent Mg alloys with continuous concentration gradients and nano-grain sizes by magnetron co-sputtering. Rapid screening of ultra-strong Mg alloys (55.84~97.89 wt% Mg) has been done as a function of Gd, Y, and Zr solutes. A positive correlation between grain size and solution chemistry with mechanical properties such as hardness and Young’s modulus, has been established by performing nanoindentation tests on the entire chemistry spectra of over 100 samples. Surprisingly, ultra-strong Mg alloys (Hardness: 5.28 GPa, Young’s modulus: 181.20 GPa) have been identified in not only the richest solute-containing alloys but also the low-alloyed alloys. The yield and ultimate tensile strengths reached 1.0 GPa and 1.4 GPa, respectively. The fundamental mechanism of the Hall–Petch relationship and solution strengthening at such conditions was revealed by using DFT calculations and TOF–SIMS, enabling subsequent discoveries of a high-strength Mg alloy materials library.