In the last few years, biodegradable Zn-based alloys are attracting constantly growing scientific attention due to their biocompatibility and more suitable degradation rate than Mg alloys. However, their major drawbacks include low mechanical strength due to the activation of grain boundary sliding, a low ability to strengthen due to low recrystallization temperature, and a lack of methods allowing refinement of coarse second-phase particles.

In the present work, we show how a processing route composed of rapid solidification (RS) by melt spinning and subsequent high-pressure torsion (HPT) affect the deformation mechanisms at room temperature. A combination of RS and HPT produced a 1.5 times smaller grain size (~300 nm) than HPT processing of conventionally cast samples. Surprisingly, grain refinement does not enhance grain boundary sliding (the expected mechanism in fine-grained Zn alloys). Instead, nanometric particles of intermetallic phases created during RS generate a pinning force for grain boundary sliding, resulting in a smaller grain size and higher ultimate tensile strength.

The production of thermally stable, ultra-fine microstructures in Zn-Li-based alloys goes only halfway to developing a complex processing route for ultrahigh-strength Zn-Li-based alloys. The strength-plasticity will be further optimized by annealing which will significantly increase strength, and only slightly reduce elongation to failure.